Click to proceed to

Table of Contents

STATE AND LOCAL MITIGATION PLANNING

how-to guide

identifying hazards

and estimating losses
STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

foreword

introduction

STEP ONE identify hazards

worksheet #1

STEP TWO profile hazard events

worksheet #2

flood hazard profiles

earthquake hazard profiles

tsunami hazard profiles

tornado hazard profiles

coastal storm hazard profiles

landslide hazard profiles

wildfire hazard profiles

i

iii

1-1

1-2

2-1

2-2

2-10

2-15

2-18

2-20

2-22

2-27

2-29

Contents

1

2
Version 1.0 August 2001

STEP THREE inventory assets

worksheet #3a

worksheet #3b

flood hazard asset inventory

earthquake hazard asset inventory

tsunami hazard asset inventory

tornado hazard asset inventory

coastal storm hazard asset inventory

landslide hazard asset inventory

wildfire hazard asset inventory

STEP FOUR estimate losses

worksheet #4

flood hazard loss estimation

earthquake hazard loss estimation

tsunami hazard loss estimation

tornado hazard loss estimation

coastal storm loss estimation

landslide hazard loss estimation

wildfire hazard loss estimation

afterword

appendix a glossary

appendix b library

appendix c worksheets

3-1

3-2

3-3

3-16

3-20

3-23

3-24

3-26

3-29

3-30

4-1

4-2

4-12

4-16

4-25

4-27

4-29

4-34

4-36

a-1

b-1

c-1

3

4
STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

the

natural

hazard

mitigation

planning

process

Natural hazard mitigation planning

is the process of figuring out how to

reduce or eliminate the loss of life

and property damage resulting from

natural hazards such as floods,

earthquakes, and tornadoes. Four

basic phases are described for the

natural hazard mitigation planning

process as shown in this diagram.

For illustration purposes, this diagram portrays a process that appears to proceed in a single direction. However, the mitigation

planning process is rarely a linear

process. It is not unusual that ideas

developed while assessing risks

should need revision and additional

information while developing the

mitigation plan, or that implementing the plan may result in new goals

or additional risk assessment.

foreword
i Version 1.0 August 2001

foreword

The Federal Emergency Management Agency (FEMA) has

developed this series of mitigation planning "how-to" guides to

assist states, communities, and tribes in enhancing their natural

hazard mitigation planning capabilities.

These guides are designed to provide the type of information

states and communities need to initiate and maintain a planning

process that will result in safer communities. These guides are

applicable to states and communities of various sizes and varying

ranges of financial and technical resources.

This how-to series is not intended to be the last word on any of the

subject matter covered; rather, it is meant to be an easy to understand guide for the field practitioner. In practice, these guides may

be supplemented with more extensive technical data and the use

of experts if possible.

The how-to guides cover the following topics:

 Getting started with the mitigation planning process

including important considerations for how you can

organize to develop a plan;

 Identifying hazards and assessing losses to your community and state;

 Setting mitigation priorities and goals for your community;

 Evaluating potential mitigation measures through the

use of benefit-cost analysis and other techniques;

 Creating a mitigation plan and implementation strategy;

 Implementing the mitigation plan including project

funding and revising the plan periodically as changes in

the community occur; and

 Incorporating special circumstances in hazard mitigation planning for historic structures, among other

topics.

mit-i-gate\ 1: to cause to

become less harsh or hostile; 2: to make less severe

or painful

plan-ning\ : the act or process of making or carrying out plans; specif: the establishment of goals, policies and procedures for a social or economic unit

The Disaster

Mitigation Act of

2000

The impetus for states and

local governments to undertake natural hazard mitigation planning was given

a significant boost on October 30, 2000,

when the President signed the Disaster Mitigation Act of 2000 (Public Law

106-390). The law encourages and rewards local and state pre-disaster planning, promotes sustainability as a strategy for disaster resistance, and is

intended to integrate state and local

planning with the aim of strengthening

statewide mitigation planning. This new

approach facilitates cooperation between state and local authorities,

prompting them to work together. This

enhanced planning network enables

local, tribal, and state governments to

articulate accurate and specific needs

for mitigation, resulting in faster allocation of funding and more effective risk

reduction projects.
ii STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Why should you spend the time to read

these guides?

 It simply costs too much to address the effects of

natural disasters only after they happen;

 Neither communities nor their residents can be made

whole by state and federal aid after disasters;

 You can prevent a surprising amount of damage from

these hazards if you take the time to anticipate where

and how these natural phenomena occur; and

 The most meaningful steps in avoiding the impacts of

natural hazards are taken at the state and local levels by

officials and community members who have a personal

stake in the outcome and/or the ability to follow

through on a sustained program of planning and

implementation.

The guides focus on showing how mitigation planning:

 Can help your community become more sustainable

and disaster-resistant through selecting the most appropriate mitigation measures, based on the knowledge

you gain in the hazard identification and loss estimation process.

 Allows you to focus your efforts on the hazard areas that are

most important to you by incorporating the concept of

determining and setting priorities.

 Can save you money by providing a forum for engaging

in partnerships that could provide technical, financial,

and/or staff resources in your effort to reduce the

effects, and hence the costs, of natural hazards.

Developing a successful natural hazard mitigation plan

for your community depends

on how well you understand

the potential problems you face. This

how-to guide is focused on the second

phase of the natural hazard mitigation

planning process and will help you estimate your losses from selected hazard events.

Click to proceed to

Introduction

Return to

Table of Contents
iii Version 1.0 August 2001

introduction

Risk assessment answers the fundamental question that fuels

the natural hazard mitigation planning process: "What would

happen if a natural hazard event occurred in your community or state?"

Risk assessment is the process of measuring the potential loss of

life, personal injury, economic injury, and property damage resulting from natural hazards by assessing the vulnerability of people,

buildings, and infrastructure to natural hazards.

Risk assessment provides the foundation for the rest of the mitigation planning process. The risk assessment process focuses your

attention on areas most in need by evaluating which populations

and facilities are most vulnerable to natural hazards and to what

extent injuries and damages may occur. It tells you:

 The hazards to which your state or community is

susceptible;

 What these hazards can do to physical, social, and

economic assets;

 Which areas are most vulnerable to damage from

these hazards; and

 The resulting cost of damages or costs avoided

through future mitigation projects.

In addition to benefiting mitigation planning, risk assessment

information also allows emergency management personnel to

establish early response priorities by identifying potential hazards

and vulnerable assets.

The steps in this how-to guide describe some methods you may use

to develop this information. Subsequent guides assist you in determining priorities for mitigation and in deciding which assets in

your community or state should be protected.

State and Local Risk Assessment

Risk assessment is a shared responsibility between states and local

communities. Both states and communities should assess their risks

from natural hazards as part of their respective planning processes.

While local governments focus on the hazards, vulnerabilities, and

risks on a local or regional scale, states should focus on the rehaz-ard\ : a source of

danger

vul-ner-a-bil-i-ty\ : open to

attack or damage

risk\ : possibility of loss or

injury

Understanding Your Risks:

Identifying Hazards & Estimating Losses is part of a series

of guides that will help you identify, plan,

and evaluate measures that can reduce

the impacts of natural hazards in your

community or state through a comprehensive and orderly process known as

Natural Hazard Mitigation Planning.

As detailed in the Foreword, the process

consists of four basic phases as shown

below. The first phase consists of creating a mitigation planning team (referred

to as the "Planning Team" in these

guides) with representatives from the

public and private sectors, citizen groups,

colleges or universities, as well as nonprofit agencies.

This guide, Understanding Your Risks,

addresses the second phase of the planning process. Guides dealing with the

third and fourth phases, “Develop a Mitigation Plan” and “Implement the Plan

and Monitor Progress”, discuss establishing goals and priorities, selecting mitigation projects, conducting benefit-cost

analyses, and writing, implementing, and

revisiting the mitigation plan.
iv STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

gional and statewide implications of hazards. The risk assessment

process introduced in this guide encourages the reciprocity of

information and support between states and local governments -

states provide leadership and support to local communities, and

local communities provide their states with local-level risk analyses.

Through this exchange of information, statewide risk assessments

based on detailed, local-level analysis are produced.

States can provide leadership early on by establishing guidelines,

setting expectations, and providing incentives for local risk assessment and mitigation planning activities. To support and facilitate

the risk assessment process, states should be able to provide communities with technical assistance, basic hazard data, and access to

a range of state agency technical resources. Key decisions must be

made by states to ensure a level of consistency in local risk data to

facilitate statewide analysis.

As states gain a greater understanding of where the highest risks

are across the state, they will be better prepared to decide where

and how mitigation resources can be most effective. This information will become part of the state's mitigation plan, where mitigation priorities and criteria for those priorities are articulated.

How do you use this guide?

Understanding Your Risks provides detailed, step-by-step instructions

on the procedures which are part of the Assessing Risks phase of

the Natural Hazard Mitigation Planning Process. The recommended steps in this guide, shown here, are organized into four

simple steps to estimate losses from a single hazard event. More

complex risk assessment processes use complicated statistical

analysis of a wide range of past hazard events and geological,

climatic and meteorological data to determine probable losses on

an annual basis. The intent of this how-to guide is to help you

develop a baseline estimate of possible losses throughout your

community or state from one event.

Losses, as used here, are represented as the monetary damage to

structures and contents, interruption of services, and displacement

of residents and businesses. The use of money as a measure of loss

serves several purposes:

 It conveys the financial cost of a disaster to a community. It is important to note that there are other intangible losses that occur in a community such as losses of

historic or cultural integrity or damage to the environment that are difficult to quantify. Other costs, includ-
introduction

Version 1.0 August 2001 v

ing response and recovery costs, are often unrecoverable (these costs are not addressed in this guide).

 It provides an explicit representation of what a community or state stands to lose in a disaster. This is

useful for elected officials and other decision makers

who will need to balance the costs of mitigation against

the costs of damage.

 It provides comparable measurements of losses across

different hazards or different parts of the community. It

assists a community in determining which hazards or

what parts of the community to focus on.

 It provides a dollar amount to use as part of a benefitcost analysis to be applied later (in subsequent how-to

guides) in determining the cost-effectiveness of mitigation initiatives.

After you have estimated losses using one hazard event, you may

find it necessary to conduct a comprehensive risk assessment by

assessing the full range of hazard events. The work you produce

here will serve as a good foundation for this additional effort if the

need arises but will be of immediate benefit in helping set priorities and identifying mitigation projects in the next phase of the

planning process – “Develop a Mitigation Plan”.

Multi-Hazard Guidance

Where appropriate, this guide includes specific information to

estimate losses for seven natural hazards, with a unique icon to

identify each:

Floods Coastal Storms

Earthquakes Landslides

Tsunamis Wildfires

Tornadoes

Obviously, there are other hazards that can affect states and

communities. While this guide does not provide specific direction for all hazards, the basic procedures explained here could

be adapted for any natural hazard with variations that respond to

Comprehensive

Risk Assessment

Later in the planning process

(the third and fourth phases),

you will have enough information to decide what mitigation actions you will pursue, and how they may be funded. Potential mitigation projects that will use

federal funding require an analysis of

benefits and costs across a broad range

of hazard events. If you plan to use federal funding, it may be necessary to

conduct a comprehensive hazard profile by considering all possible hazard

events. For example, a devastating flood

may occur every thousand years, however there’s also a chance of a minor

level of flooding every year, although the

depth will obviously be much less. The

small annual floods may result in far

more damage than one big flood that

may only occur once a century. In a rigorous risk assessment or benefit-cost

analysis, mathematical calculations are

used to determine the expected damages from the whole range of possible

flood events, or other hazards that could

impact an area. This provides a more

accurate and complete picture of risk

(and the benefits of avoiding it) than the

“single-point” method. The procedures

for doing an analysis with FEMA benefit-cost analysis software are simple

and are discussed as part of the “howto” guide for the third phase of the planning process, “Develop a Mitigation

Plan”.
vi STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

the peculiar nature of each hazard. For a more complete description of the range of natural hazards that can affect the

United States, please see Multihazard Identification and Risk

Assessment published by FEMA.

State and Local Guidance

This guide is focused on providing guidance to communities,

tribes, and states. While much of the hazard identification and loss

estimation process operates in a similar fashion for each level of

government, there are critical points where estimating losses for

communities and tribes and states are different due to the differences in size. Therefore, throughout this document, guidance

focused solely on the role of the “States“ is identified as a sidebar

with this icon. Furthermore, guidance focussing on communities

includes tribes as well.

Types of Information

In addition to helpful hints and useful information identified by

the “Tips” icon, this guide also provides a number of options that

can be used in situations where detailed information is not readily

available.

You should follow the main procedures outlined in this guide to

produce your loss estimation. However, when you are unable to get

desired information, such as the Flood Insurance Rate Map, or

when a procedural shortcut may exist, the alternative method will

be identified by the “Basic” icon.

In addition to the alternative method, advanced information has

also been provided and will be identified by the “Advanced” icon.

This method can be used to refine your loss estimation to improve

your results or when specialists may be needed.

The “HAZUS” icon identifies suggestions for using the risk assessment tool, HAZUS (Hazards U.S.). In addition to estimating

earthquake losses, HAZUS contains a database of economic,

census, building stock, transportation facilities, local geology, and

other information that can be used for a number of steps in the

risk assessment process.

Finally, the “Caution” icon will alert you to important information

about the risk assessment process.
introduction

vii Version 1.0 August 2001

Glossary

The “Glossary” icon identifies terms and concepts that need

further explanation. These and other common risk assessmentrelated terms and phrases are defined in the Glossary included in

Appendix A.

Library

In addition, a risk assessment “Library” has been included in

Appendix B. The library has a wealth of information, including

Web addresses, reference books, street addresses, and phone

numbers to help you conduct your loss estimation. Each of the

Websites and references listed in this how-to guide are included in

the library.

Hazardville

Applications of the various steps in the risk assessment process will

be illustrated through a fictional community, the Town of

Hazardville. Hazardville, located in the State of Emergency, is on a

quest to develop a natural hazard mitigation plan, which includes

an estimate of potential losses. Hazardville is a small community

with limited resources and multiple hazards. When we left

Hazardville after the first phase of the planning process, “Organize

Resources,” the town had just established its mitigation planning

team, the Town of Hazardville Organization for Risk Reduction

(THORR). Fictional newspaper accounts featuring the THORR

will illustrate the various steps in the risk assessment process (see

page xi).

Worksheets

Finally, to help you obtain the information you need at each step

of the process, worksheets have been developed to correspond

with the structure of this guide. In each step, examples of the type

of information to be included in these worksheets are shown. All

of the worksheets have also been included in Appendix C at the

end of this guide. You should photocopy these forms and record

your progress as you undertake this risk assessment process. Alternatively, you may use the worksheets as templates with which to set

up your own computer spreadsheets, databases, or other applications.

During the development of a mitigation

plan, you will need to

gather information and data

from a number of sources.

As with any effort of this type, it is important to be aware of how different authors use terms. The easiest way is to

make sure you look for specific definitions within the source documents to

be sure you understand the intended

meaning.

Please keep in mind

that the World Wide Web is

an ever-changing source of

information and that web addresses and the information

they contain will change over

time.
viii STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Getting Started

This guide will help you answer the following questions:

What kinds of natural hazards can affect your state or community?

What may have happened in the past that you should know about?

Quite naturally, many people are only aware of the most obvious

risks, usually as a result of a disaster that affected their community or state in the recent past such as a tornado, hurricane, or

flood. In many cases, however, there are hazards most people are

not aware of because they haven't affected the community or

state during the lifetimes of current residents.

Step 1 of this guide – Identify Hazards – helps explain how to determine

which natural hazards can affect you.

How bad can it get?

How "big" is each hazard's potential impact? Will it affect every area the

same or will certain areas get hit harder than others? How often will each

type of hazard impact your community or state?

It's important to know the location and amount of land area that

may be affected by certain kinds of hazards. For example, there

may be areas that can be affected repetitively by a hazard in one

part of the community (such as floodplains adjacent to streams and

rivers) or there may be potential community-wide impacts from

events such as hurricanes or earthquakes. You should also note

that a specific type of hazard can have varying effects on a community, depending on the severity of individual hazard events. For

example, differences in the depth of floodwaters from discrete

flood events will yield corresponding differences in the amount of

damages.

Step 2 of this guide – Profile Hazard Events – will help you determine how

bad a hazard can get.

What will be affected by these hazards?

Are there buildings, roads, and/or other facilities in the community that

will be damaged or destroyed by these hazards? Are there concentrations of

certain populations in hazard areas that are especially vulnerable, such as

elderly or non-English speaking people?

An inventory will help you identify the assets that can be damaged

or affected by the hazard event. For detailed assessments, the

inventory will also include information on special populations and

Many Midwestern

communities are located near the New Madrid

fault, an area with a high

seismic risk; however, most

residents are not aware of this risk because the last significant earthquake

occurred in the early 19th Century. In

addition, many arid regions of the country face significant risk due to flooding,

even though most of their watercourses

are dry. When heavy rains occur in

these areas, the storms can be very intense and cause flash floods on hillsides

(alluvial fans) and in "dry" streambeds.

Even within the

same hazard event,

there can be different types

of impacts. Hurricanes can

cause flooding due to torrential rains across broad coastal and inland areas. However, along the shoreline, hurricanes and other coastal

storms can cause an increase in the

mean sea level, called a "storm surge".

As communities

and states work together to generate statewide mitigation plans, many

communities may want to

update or revise their risk assessment

to assess risks from several hazard

events encompassing a range of intensities and/or frequencies or to determine future risks.
introduction

Version 1.0 August 2001 ix

building characteristics like size, replacement value, content

value, and occupancy. In many cases, community assets may be

vulnerable to more than one type of hazard, and you may need

to look at different characteristics of the same asset to understand its vulnerability to each type of hazard. For example, if a

building is subject to both floods and earthquakes, you will be

interested in the location and elevation of the building so you

can tell how much of its structure and contents will be damaged

by flooding. You will also be interested in the construction of the

building and its ability to resist physical damage caused by the

anticipated ground movements during an earthquake.

Step 3 of this guide – Inventory Assets – will help you determine where

and/or to what extent these hazards will affect the assets of your community

or state.

How will these hazards affect you?

What are the varying effects of different hazards on community assets? To

what extent will assets be damaged by each hazard? If buildings and other

structures are destroyed or damaged, how much will it cost to replace and/

or repair them? If the contents of businesses and homes are also affected,

how much cost would be added? If there are indirect effects, what is the

accumulated cost of the losses?

Hazards create direct damages, indirect effects, and secondary

hazards to the community. Direct damages are caused immediately

by the event itself, such as a bridge washing out during a flood.

Indirect effects usually involve interruptions in asset operations

and community functions, also called functional use. For example,

when a bridge is closed due to a flood, traffic is delayed or rerouted, which then impacts individuals, businesses, and public

services, like fire and police departments that depend on the

bridge for transportation. Secondary hazards are caused by the

initial hazard event, such as when an earthquake causes a tsunami,

landslide, or dam break. While these are disasters in their own

right, their consequent damages should be included in the damage

calculations of the initial hazard event. Your loss estimations will

include a determination of the extent of direct damages to property, indirect effects on functional use, and the damages from

secondary hazards for each of the hazards that threaten your

community or state.

Step 4 of this guide – Estimate Losses – will help you determine how

hazards will affect your community or state.

It is important to continually provide citizens with the information gained

throughout the risk assessment process. This not only educates the community on their hazards and risks in an

ongoing fashion, but facilitates wider involvement in the process. Holding public meetings to present the most recent

findings after each major step in the risk

assessment process allows the new

information to be reviewed and validated. Making sure that media coverage of the process is regularly engaged is another

technique for ensuring that

no interested parties are left

out of the process.
x STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

____

Go to Step 1

After you have read this Introduction and reconvened your Planning Team, go to Step 1. In Step 1, you will identify all of your

potential hazards and determine which hazards are most prevalent in your community.

____
introduction

xi Version 1.0 August 2001

The Hazardville Post

Vol. CXI No. 65 Thursday, March 6, 2001

Risky

Business

[Hazardville, EM] The

Hazardville Town Council

unanimously approved the

creation of the Town of

Hazardville Organization for

Risk Reduction (THORR) at

a meeting last night. In anticipation of the move, Mayor

McDonald nominated

THORR members last month.

The THORR members will

work with town staff to identify natural hazards that could

threaten Hazardville and estimate their losses from those

hazards. This process is

known as risk assessment. As

reported previously in the

Post, THORR will include a

number of prominent community and business leaders.

Starting next month, the Post

will launch a series of articles

covering THORR's work on

the risk assessment process.

Click to proceed to

Step 1

Return to

Table of Contents
step
1

Version 1.0 August 2001 1-1

identify

hazards

Overview

The first step in doing a risk assessment answers the question:

What kinds of natural hazards can affect your planning area?

In this step, you will simply identify all the natural hazards that

might affect your community or state and then narrow your list to

the hazards that are most likely to impact you.

Bear in mind that although a hazard may not have affected you

recently, it doesn't mean it won't in the future. You should look at

the full range of potential hazards and assess whether they may

affect the area you're including in your mitigation plan. While this

might sound daunting, there is a relatively small list of hazards to

consider.

Remember that all subsequent steps in the Natural Hazard Mitigation Planning Process are built on the information gathered

during risk assessment. As you proceed, remember to keep records

of what you've found and where you’ve found it. Your records may

include copies of documents or maps, notes on whom you talked

to and when you talked to them, Website references, and so forth.

You'll need these later in the loss estimations and in the rest of the

mitigation planning processes. Use Worksheet #1: Identify the

Hazards in Appendix C (see example on page 1-2) to keep track of

your research, and when you're finished with this step, you'll have

a list of hazards that could affect your community or state.

Procedures & Techniques

Task A. List the hazards that may occur.

There is no one source for identifying which hazards may affect

your state or community. However, the following techniques are

methods that have worked for others and should at least provide

you with a good starting point.

1. Research newspapers and other historical records.

These records will often contain dates, magnitudes of the events,

damages, and further evidence of past natural disasters in your

Remember, for now you

are simply compiling information about what hazards

affect your state or community, but later you will be assessing the risks they pose. It's a good

idea to read through the whole guide

before starting to gather information, so

you can get everything you need from

the various sources and not have to return later for additional data.

1

St. Louis tornado damage, May 27,

1896.

NOAA
1-2 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Worksheet #1 Identify the Hazards step 

Date: March, 2001 What kinds of natural hazards can affect you?

Task A. List the hazards that may occur.

1. Research newspapers and other historical records.

2. Review existing plans and reports.

3. Talk to the experts in your community, state, or

region.

4. Gather information on Internet Websites.

5. Next to the hazard list below, put a check mark in

the Task A boxes beside all hazards that may occur

in your community or state.

Task B. Focus on the most prevalent hazards in your

community or state.

1. Go to hazard Websites.

2. Locate your community or state on the Website map.

3. Determine whether you are in a high-risk area. Get more

localized information if necessary.

4. Next to the hazard list below, put a check mark in the

Task B boxes beside all hazards that pose a significant

threat.

Avalanche

Coastal Erosion

Coastal Storm

Dam Failure

Drought

Earthquake

Expansive Soils

Extreme Heat

Flood

Hailstorm

Hurricane

Land Subsidence

Landslide

Severe Winter Storm

Tornado

Tsunami

Volcano

Wildfire

Windstorm

Other____________

Other____________

Other____________

Note: Bolded hazards are addressed in

this How-To Guide.

Use this space to record information you find for each of the hazards you will be

researching. Attach additional pages as necessary.

Hazard or Event Description

(type of hazard, date of event, number of

injuries, cost and types of damage, etc.)

Source of

Information

Map

Available

for this

Hazard?

Scale of

Map

Task A Task B



 

 

 





 



 

 

 

Flood - June 1936. 500-year flood. One

death, some corn & crop losses.

• Members of

community

• Newspaper

• Floodplain

manager

FIRM 1 : 6000

Hurricane Camille - Nov. 1969. One death.

Flooding & wind caused $1.5 million in

damages.

• Newspaper

• Internet

research

1 : 24000

1 : 24000

1 : 6000

1 : 6000

• Newspaper

• State

geologist

• Newspaper

• State fire

marshal

• Newspaper

Severe storm caused flooding & landslides -

May 1973. $2 million in damages.

Severe storm & tornadoes - April 1980.

Wind & flash floods caused $1.5 million in

damages.

Wildfires - April 1981.

1,050 acres burned.

Topographic

USDA &

fuel model

maps.

FIRM &

storm

surge map

Topographic &

soils maps

No
identify hazards 1

Version 1.0 August 2001 1-3

community or state. A public library may also have documentation

on these events in the "local history" section. Local historical

societies may also be good sources of information.

2. Review existing plans and reports.

The preceding techniques are focused on local sources of information that will likely provide a good start to the process. However, to

ensure you are covering all of the possible hazards, you will want to

broaden the contacts you make. There are many types of plans and

documents that may have information on natural hazards in your

community or state. Many states will already have mitigation plans,

hazard identification reports, and/or risk assessment reports. State

transportation, environmental, dam, or public works reports or

plans may also contain relevant information. Although these may

not contain a lot of details about local hazard conditions, they

offer a good starting point for communities, and using them

improves consistency among communities within the state. Review

the plans for a list of hazards that can occur in the state or for a list

of disasters that have occurred in the past.

Local comprehensive plans, land use plans, capital improvement

plans, as well as building codes, land development regulations, and

flood ordinances may contain hazard provisions that indicate the

presence of local hazards. You should review these to determine

whether a local hazard exists.

3. Talk to the experts in your community, state, or region.

There are many sources of hazard information in government,

academia, and the private sector. Many local floodplain managers,

departments of public works, engineering, planning and zoning,

and transportation departments maintain information about

natural hazards. Those who would have been involved with past

natural hazard events such as the police and fire departments or

the local emergency management staff are also excellent sources

of information on past hazard events. Furthermore, state agencies,

including water or natural resources, geological survey, and emergency management will have detailed knowledge about the nature

and extent of hazards in your state. University departments, including planning, landscape architecture, geography, and engineering

may already have hazard maps or can help you obtain them. Many

local businesses that provide hazard related services might be

willing to assist you.

Your best source of hazard information will often be your state.

The State Hazard Mitigation Officer (SHMO) will know what

hazards affect your state, and is also a good source for suggestions

State emergency

management departments are sometimes housed in larger agencies such as state police,

military, or public safety.

The informationyou

discover in the newspapers and on the Internet will

help you when you talk to

hazard experts in your community. It will provide you with technical

terms and general factual information

about the various hazards, in addition

to helping you identify the appropriate

experts to contact.
1-4 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

about where to go for more detailed information. Bear in mind

that the SHMO may not have specific information about the

hazards that affect a particular community but will probably be

knowledgeable about your area of the state and will often be able

to suggest other people to talk to or additional resources.

4. Gather information on Internet Websites.

The library at the end of this guide lists many such sites. These

may be hazard-specific sites that provide general information about

why particular hazard events happen, what the probabilities of

occurrence are, and how hazards are measured. Other Websites

will have state-specific, or even site-specific information about the

hazards in a particular area and about the characteristics of the

hazards, such as the probability, history of events, and expected

severity.

Task B. Focus on the most prevalent hazards in your

community or state.

If your preliminary research reveals that your community or state

has been affected by a particular hazard or that experts consider

your area to be threatened by that hazard, you will concentrate

further research on it in later steps.

If your planning area has not experienced a hazard event in recent

memory but one of the sources indicates it is a possibility, it may be

worth a little extra effort to confirm that a particular hazard type is

relevant.

1. Go to the indicated Websites for the seven major hazards to

help you determine whether your community or state can be

affected by the hazard.

2. Locate the approximate location of your community or state

on the Website map.

3. Examine the map to determine whether you are located in a

high-risk area for that hazard and to determine the chance it

will occur in your planning area. You may need to get more

localized information for some of the hazards.

4. You may find that you can delete some hazards from your list

at this time; however, if you are unsure or uncomfortable with

the chance of the hazard occurring, it's better to keep all

potential hazards on the list, until you are certain that it is

appropriate to remove it.

Research past Presidentially declared disasters, as

well as non-declared severe

events that have occurred in

your state and in other states

within your region. You should inquire

into the types of hazards that have occurred in the adjoining states as well.

Communicate this information to your

communities.

Search database or computerized archives with the

following list of hazards as

keywords. Narrow the search

by using the name of your

community, state, or surrounding states

as keywords (the following list not meant

to cover all known natural hazards).

Avalanche

Coastal Erosion

Coastal Storm

Dam Failure

Debris Flow

Drought

Earthquake

Expansive Soils

Extreme Heat

Flood

Hailstorm

Hurricane

Land Subsidence

Landslide

Severe Winter Storm

Tornado

Tsunami

Volcano

Wildfire

Windstorm
identify hazards 1

Version 1.0 August 2001 1-5

The Hazardville Post

Vol. CXI No. 100 Thursday, April 10, 2001

The Organization for Risk Reduction Seeks Danger

(Part 1 of a 4 Part Series on the Risk Assessment Process)

[Hazardville, EM] The Town of

Hazardville Organization for Risk Reduction (THORR) is on a mission to find

out about the natural hazards that

threaten Hazardville. The task force, appointed by Mayor McDonald, will develop a hazard mitigation strategy to reduce the town's vulnerability to natural

hazards such as floods, hurricanes, and

earthquakes. While the process of researching the town's potential hazards

is not exactly fraught with danger, "the

task force is using a lot of different resources to discover the past and possibly future impacts from hazards," said

Joe Norris, the task force lead planner.

THORR began researching past impacts from hazards simply by talking to

people in the community. "You'd be surprised just how much information

people know and remember about the

disasters from years ago," said Norris.

"We visited an elderly man who lives

near Raging River who vividly recalled

the Flood of 1936. While there was not

much of a human toll because the Raging River area was largely rural, agricultural, and forested at the time, this

man recalled that the fast-moving waters were apparently quite deep." Norris

noted that a search of local newspaper

archives confirmed the flood, as did a

conversation with the Floodplain Manager. "She said that the flood was estimated to be a 500-year event - something that has only a 0.2% chance of happening annually."

Another resource the task force has

tapped is the State Hazard Mitigation Officer (SHMO). The SHMO provided

THORR with a copy of the state hazard

mitigation plan, which discussed past disasters that have

occurred in the

State of Emergency. THORR

has found the

document to be

useful in describing the likelihood

that certain hazard events will

occur in Emergency. An even

more valuable resource provided

by the SHMO has

been contact with

various hazard

experts in state

government.

"They're free!"

laughed Norris,

alluding to a concern expressed

by the Town

Council that a

risk assessment

may be an expensive endeavor.

Norris remarked that THORR has

found the State Geologist to be especially helpful in furnishing information

on earthquakes and landslides. According to the State Geologist, Hazardville

sits squarely in the middle of an earthquake zone, about 100 miles from the

New Temptfate fault. "I know we've experienced a few tremors over the years,

even some collapsed chimneys from one

of the stronger tremors, but I had no idea

the potential for stronger earthquakes

existed in Hazardville."

DATE TYPE OF INCIDENT

N e ovember 7, 1969* Hurricane Camill

A g pril 9, 1970 Heavy Rain, Tornadoes, Floodin

M ) arch 27, 1973 Earthquake Tremors (offshore

M g ay 29, 1973* Severe Storms, Landslides, Floodin

O g ctober 2, 1975 Severe Storms, Tornadoes, Floodin

A g pril 9, 1977* Landslides, Floodin

M t arch-October, 1977 Drough

M e arch 17, 1979* Wildfir

A g pril 18, 1979* Storms, Wind, Floodin

A g pril 20, 1980* Severe Storms, Tornadoes, Floodin

A e pril 10, 1981* Wildfir

M s ay 11, 1984 Earthquake Tremor

S a eptember 7, 1985* Hurricane Elen

M g arch 21, 1990 Severe Storms, Tornadoes, Floodin

J g anuary 4, 1991 Severe Storms. Floodin

M g arch 3, 1994* Severe Winter Storms, Freezing, Floodin

J i uly 8, 1994* Offshore Earthquake, Tsunam

A g pril 21, 1995 Severe Storms, Landslides, Floodin

M g arch 20, 1996* Severe Storms, Landslides, Floodin

A ) pril 29, 1998* Flooding (Tropical Storm Zoe

S e eptember 15, 1999* Wildfir

N s ovember 10, 1999 Earthquake, Aftershock

* State or Presidentially declared disaster

Through its research, THORR has

uncovered information on many large

and small hazard events. In fact, on 13

occasions from 1969 to 1999, these

events have met the criteria to be state

or federally declared disasters. The list

of events THORR has researched appears above.

When asked what the next steps are

for THORR, Norris responded,

"THORR will continue to research these

hazards. The more information we have,

the better our risk assessment will be."
1-6 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Floods

Source: http://www.esri.com/hazards/

Source: FEMA

Floods are the most prevalent

hazard in the United States. This

map illustrates where there have

been past Presidential declarations

for flood events. FEMA has prepared Flood Insurance Studies

(FIS) for floodprone communities. These FISs contain information on local flood history, local

flood problems, and other flood

studies that have been prepared

for the community.

FEMA has also created Flood

Insurance Rate Maps (FIRM) for

more than 19,000 communities in

the country as a part of the FIS. In

addition to the 100-year floodplain, which is the area of the

community with a 1% chance of

flooding in any given year, the

FIRM also illustrates coastal high

hazard areas, the floodway, and

the 500-year floodplain, which is

the area of the community with a

0.2% chance of flooding in any

given year.

Digital Quality Level 3 flood data

(Q3) are available for 1,200

counties in CD-ROM format from

FEMA. A list of counties is available at http://msc.fema.gov/MSC/

statemap.htm The digital Q3 flood

data are a digital representation of

certain features on FIRMs and can

also be viewed in HAZUS.

1 Review your FIRM or Q3 to identify areas prone to flooding. Alternatively, go to

www.esri.com/hazards to conduct a preliminary identification of flood hazards using

digital Q3 flood data available online.

2 Go to Step 2 for information on acquiring flood maps and on profiling your flood hazard.
identify hazards 1

Version 1.0 August 2001 1-7

Earthquakes

Source: http://geohazards.cr.usgs.gov/eq/pubmaps/US.pga.050.map.gif

1 Go to the http://

geohazards.cr.usgs.gov/eq/

pubmaps/US.pga.050.map.

gif Website to determine

whether you are located in

an earthquake hazard zone.

2 Find the approximate location of your community or

state on the seismic hazard

map.

3 If you are located in an area

with 2%g (peak acceleration) or less, then you have a

relatively low seismic risk and

can probably avoid conducting an earthquake risk

assessment at this time.

However, you should confirm

your findings with your state

geologist or emergency

manager.

4 If you are located in an area

with 3% g peak acceleration

or more, then you should

proceed to Step 2 to profile

your earthquake hazard.
1-8 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Tsunamis

Source: http://www.pmel.noaa.gov/~bernard/senatec.html

1 Go to the http://www.pmel.

noaa.gov/~bernard/senatec.

html Website. This page will

show population centers on

the West Coast of the

United States that are at risk

of tsunamis.

2 Find the approximate

location of your community

or state on the tsunami map.

3 If you are not located on the

West Coast, a Pacific Island,

or a Caribbean Island*, then

you have a relatively low

tsunami risk and can probably avoid conducting a

tsunami risk assessment at

this time. However, you

should confirm your findings

with your state geologist or

emergency manager.

4 If you are located in communities along the shoreline,

along coastal estuaries, or

along rivers affected by tides

in Alaska, Washington,

Oregon, California, Hawaii,

or Puerto Rico, then you

should proceed to Step 2 to

profile your tsunami hazard.

*NOTE:

Recent findings indicate that tsunamis are also possible along the Atlantic Ocean

coastal areas of Virginia and North Carolina. As more information become available, these areas may also wish to include tsunamis in their risk assessment.
identify hazards 1

Version 1.0 August 2001 1-9

Source: FEMA

3 If you are not located in

one of the four colored

zones or special wind

regions on the map

above, you can probably

avoid conducting a

tornado risk assessment

at this time. However,

you should confirm your

findings with your state

meteorologist or emergency manager.

4 If you are located in one

of the four colored zones

or special wind regions

on the map above, then

you should proceed to

Step 2 to profile your

tornado hazard.

Source: hhttp://www.fema.gov/graphics/library/wmap.gif

Tornadoes

1 Go to the http://www.fema.

gov/graphics/library/wmap.gif

Website. This page shows the

wind zones throughout the

United States. These wind

zones are based on historical

information on tornadoes

and hurricanes. The map

below illustrates areas where

Presidential declarations

have been issued for tornadoes in the past.

2 Locate your community or

state on the US Wind Zone

map.
1-10 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Coastal Storms

1 Go to the http://www.aoml.

noaa.gov/hrd/tcfaq/tcfaqG.

html#G12 Website. This page

illustrates the probabilities of

a named storm for the

Atlantic Seaboard and the

Gulf of Mexico. The map

below illustrates where

Presidential declarations

have been issued for past

hurricanes.

2 Locate your community or

state on the coastal storm

probability map.

3 If you are not located in a

coastal storm probability

zone you can probably avoid

conducting a coastal storm

risk assessment at this time.

However, you should confirm

your findings with your state

coastal zone manager or

floodplain manager.

4 If you are located in a coastal

storm probability zone, then

you should proceed to Step 2

to profile your coastal storm

hazard.

Source: FEMA

Source: http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqG.html#G12
identify hazards 1

Version 1.0 August 2001 1-11

Landslides

Source: http://landslides.usgs.gov/html_files/landslides/nationalmap/national.html

1 Go to the http://landslides.

usgs.gov/html_files/

landslides/nationalmap/

national.html Website. This

page illustrates large-scale

landslide risk areas.

2 Locate your community or

state on the landslide hazard

map. The Website listed

above allows you to zoom in

to different regions for a

closer look at the landslide

risk. While this map gives a

broad indication of largescale risk at a national scale,

it is important to know that

landslides should be evaluated at a local scale. The

map shown above is not

suitable for small-scale,

community-level hazard

identification.

3 You should discuss landslide

potential with your state

geologist, who can be found

at http://www.kgs.ukans.

edu/AASG, and with your

local public works director.

4 If either your state geologist

or local public works director

indicates a landslide risk in

your community or state, you

should proceed to Step 2.
1-12 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Wildfires

1 Go to the http://www.fs.fed.

us/land/wfas/fd_class.gif

Website. This page illustrates

the current fire danger

conditions and changes daily

based on current and past

weather, fuel types, and fuel

moisture. The map below

illustrates where Presidential

declarations have been

issued for forest fires in the

past.

2 Locate your community or

state on the fire danger map.

3 If you are located in or near

a low to moderate fire

danger class and not located

near forest, grasslands, or

dense wooded areas then you have a relatively low wildfire risk and probably can avoid conducting

a wildfire risk assessment at this time. However, you should confirm your findings with your state

fire marshal, forestry department, natural resources department or park service.

4 If you are located in or near a

dense woodland, forest or

grassland area, or have a high

to extreme fire danger class,

have experienced a prolonged dry period, or have

experienced past wildfires,

you should proceed to Step 2

to profile your wildfire

hazard.

Source: FEMA

Source: http://www.fs.fed.us/land/wfas/fd_class.gif
identify hazards 1

Version 1.0 August 2001 1-13

Keep your research

handy because after your

risk assessment is complete,

you will use this information

to help complete your hazard mitigation plan as part of the third phase in

the Natural Hazard Mitigation Planning

Process.

Summary

When you're finished with Step 1, you'll have a list of hazards that

could affect your community or state. At this point, it isn't necessary to know anything specific about the hazards except that they

are likely to occur.

You will also have a list of plans, reports, Websites, articles, and

other resources that can help you later in the process as you

determine how these hazards can affect your community.

Through your research, you will begin to foster relationships with

experts in the state and local community. This network will continue to be of use to the Planning Team as you continue to analyze

the effects of the hazards, and throughout the planning process.

____

After you have identified all of your hazards and determined which

hazards are most prevalent in your community or state

Go to Step 2

to use the information you have gathered to develop hazard

profiles.

____

Click to proceed to

Step 2

Return to

Table of Contents
step
2

Version 1.0 August 2001 2-1

profile

hazard

Overview events

With a list of potential hazards in hand from Step 1, the

next step is to develop hazard event profiles, which answers

the question: How bad can it get?

The information gathered in this step will help determine the assets

in the hazard areas you will inventory in Step 3.

Each hazard type has unique characteristics that can impact your

community or state. For example, an earthquake causes ground

shaking that will affect a community much differently than the

wind of a tornado. In addition, a given hazard type can produce

different effects depending on its magnitude, duration, or intensity.

For example, no two wildfires will impact a community in the same

way twice because the wildfire is driven by distinct wind and fuel

conditions, which can change very rapidly. Furthermore, the same

hazard events will affect different communities in different ways,

based on geography, development, population distribution, age of

buildings, etc. A hazard event is a specific occurrence of a particular

type of hazard.

For these reasons, the information you gather for each of your

hazard event profiles will reflect these different characteristics.

Some hazards, such as floods, coastal storms, wildfires, tsunamis, and

landslides will be profiled by mapping the geographic extent of

identifiable hazard events because they occur in predictable areas of

the community or state. Once the extent of these events is mapped

you will be able to determine which portion of your community or

state is vulnerable in Step 3 and begin taking inventory of the

elements that can be damaged. Other hazards, such as tornadoes

(which can occur anywhere), may be profiled simply by recording

the maximum potential wind speed. This type of information will be

used in Step 4 to evaluate the potential impact to individual structures or elements in your jurisdiction.

This step is structured to explain the basic procedures and techniques for profiling hazard events. It then instructs you on how to

gather specific hazard event profile information. Use Worksheet #2:

Profile Hazard Events in Appendix C (see example on page 2-2) to

help you record and keep track of your results.

Lee County, Georgia during the 1995

Spring floods.

The glossary in Appendix A explains the relationship

between a hazard and hazard event.
2-2 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Worksheet #2 Profile Hazard Events step

Date: May, 2001 How Bad Can It Get?

Task A. Obtain or create a base map.

You can use existing maps from:

• Road maps

• USGS topographic maps or Digital Orthophoto

Quarter Quads (DOQQ)

• Topographic and/or planimetric maps from other

agencies

• Aerial topographic and/or planimetric maps

OR you can create

a base map using:

 •Field surveys

• GIS software

• CADD software

• Digitized paper

maps

Title of Map Scale Date

Task B. Obtain a hazard event profile.

Check box when complete and fill in source of information.

Task C. Record your hazard event profile

information. Check box when complete.

 1. Get a copy of your FIRM. ______________________________

 2. Verify the FIRM is up-to-date and complete. _________________

__________________________________________________

1. Go to the http://geohazards.cr.usgs.gov Website.

 2. Locate your planning area on the map.

 3. Determine your PGA.

 1. Get a copy of your tsunami inundation zone map. _____________

__________________________________________________

 1. Find your design wind speed. ____________________________

__________________________________________________

 1. Get a copy of your FIRM. ______________________________

 2. Verify that the FIRM is up-to-date and complete.

__________________________________________________

 3. Determine the annual rate of coastal erosion.

__________________________________________________

 4. Find your design wind speed.

__________________________________________________

 1. Map location of previous landslides. _______________________

 2. Map the topography. __________________________________

 3. Map the geology. _____________________________________

 4. Identify the high-hazard areas on your map. _________________

 1. Map the fuel models located within the urban-wildland interface

areas. _____________________________________________

 2. Map the topography. __________________________________

 3. Determine your critical fire weather frequency. _______________

 4. Determine your fire hazard severity. _______________________

 1. Map the hazard. ______________________________________

 1. Transfer the boundaries from your FIRM onto your

base map (floodway, 100-yr flood, 500-yr flood).

 2. Transfer the BFEs onto your base map.

 1. Record your PGA: _____________________

 2. If you have more than one PGA print, download or

order your PGA map.

 1. Copy the boundary of your tsunami inundation

zone onto your base map.

 1. Record your design wind speed: _________

 2. If you have more than one design wind speed,

print, download, or copy your design wind speed

zones, copy the boundary of your design wind

speed zones on your base map, then record the

design wind speed zones on your base map.

 1. Transfer the boundaries of your coastal storm

hazard areas onto your base map.

 2. Transfer the BFEs onto your base map.

 3. Record the erosion rates on your base map:

__________________________

 4. Record the design wind speed here and on your

base map: ________________

 1. Mark the areas susceptible to landslides onto

your base map.

 1. Draw the boundaries of your wildfire hazard areas

onto your base map.

Other 1. Record hazard event info on your base map.

Flood

Earthquake

Tsunami

Tornado

Coastal

Storm

Landslide

Wildfire

USGS topographic 1:24,000 1995

































































FEMA Map Service Center

Hazardville Planning Dept. & floodplain manager

West Coast/Alaska Tsunami Warning Center of NOAA

Hazardville Building Inspector/Building Code

FEMA Map Service Center

Hazardville Planning Dept. & floodplain manager

State Coastal Zone Manager

Hazardville Building Inspector/Building Code

University study

USGS topographic maps

U.S Natural Resources Conservation Service soil maps

National Fire Danger Rating

USGS topographic map State Fire Marshal

How-To pg. 2-34
Version 1.0 August 2001 2-3

profile hazard events 2

Procedures & Techniques

Task A. Obtain/create a base map.

When you start the hazard event profiling process, you should

locate or create a base map so that you can show the areas that are

subject to various hazards. A base map should be as complete,

accurate, and current as possible and should be planimetric, which

is a flat representation of information in true geographic relationship (to scale) with measurable horizontal distances. Other than

distinguishable buildings, roads, rivers, coastlines, place names, and

a north arrow, the map should be as uncluttered as possible. Use an

existing map or controlled photograph as a base to avoid the cost of

producing a new map.

Maps provide common frames of reference when describing where

and how hazards can affect you. Your base map will be essential in

Step 3 by showing the human and structural assets that should be

inventoried. HAZUS should be considered first as your primary

source of hazard data. (See “Tip” on page 2-5 for information on

base maps.)

HAZUS – A Risk

Assessment Tool

Hazards U.S. (HAZUS), is a

standardized, nationally applicable earthquake loss estimation methodology that uses PC-based GIS

software. HAZUS contains an extensive

inventory of data that can help you conduct your loss estimation in a timely, costefficient manner.

Although HAZUS was originally designed

to be used to estimate earthquake losses,

it has a wider applicability to be used as a

mapping and inventory collection tool. For

example, you can use the HAZUS default

data to identify the census tracts located

in your community or state as your base

map.

Default data contained in HAZUS

Demographic data (population,

age, ethnicity, and income);

General building stock (square

footage of occupancy classes for

each census tract);

Medical care facilities;

Emergency response facilities (fire,

police, emergency operation centers);

Schools;

Dams;

Hazardous material facilities;

Roads, airports, and other transportation facilities; and

Electric power, oil, and gas lines and

other utility facilities.

Minimum System Requirements for

HAZUS99

Intel Pentium® class IMP compatible, 400 MHz or greater is recommended

CD-ROM drive

Hard drive (minimum 1 GB free

space required)

Color printer or plotter

Microsoft Windows® 95 or greater

MapInfo® 5.5/5.0 software or

ArcView® 3.2/3.1 GIS software

Minimum System Requirements for

HAZUS97

Intel 486® or greater IBM compatible computer, Pentium® preferred

CD-ROM drive

Hard drive (minimum 200 MB free

space required)

Color printer or plotter

Microsoft Windows® 3.1 or greater

MapInfo® 4.1.2 software or

ArcView® 3.0 GIS software

HAZUS is available from the FEMA Distribution Center at http://www.fema.gov/

hazus/

The HAZUS package contains a user

manual to get you started. If your community does not have someone with the

technical resources or expertise needed

to use HAZUS ask your regional/or state

planning, geology, or transportation department, or enlist the help of your local

college or university geography, planning,

or landscape architecture department to

create the maps for you. You may also

consider partnering with a private business in your planning area or hiring someone to assist you.
2-4 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task B. Obtain hazard event profile information.

In each of the seven hazard-specific sections that follow, you will be

given guidance on how to obtain, download, view, or order the

relevant hazard map or other profile information. The suggested

choice of return frequency for each hazard is based on the most

commonly available information for a particular hazard.

You will purposely consider just one hazard event in each hazard

section that follows to keep the process simple. For example, you

will consider only the 100-year flood event. A more comprehensive

hazard profile that considers all possible events, such as floods with

different probabilities, may still be needed at some future date, but

for now, this simplified version will be adequate to help you learn

more about your community's risks and narrow your focus for future

planning efforts.

Task C. Record your hazard event profile information.

Use Worksheet #2: Profile Hazard Events to record your research for

each hazard profile. Keep track of where you found various maps,

such as FIRMs, or hazard event data, such as your design wind

speed.

The type of hazard will determine whether you will record the

relevant data on the worksheet or copy the boundaries of the

hazard event onto your base map.

Summary

When you are finished with this step, you'll either have a map

showing the area impacted by each hazard type or you will have an

important piece of data regarding the characteristics of hazard

events affecting your planning area. In some cases, such as those

involving floods, you will have both.

The hazard specific sections that follow contain step-by-step instructions to help you profile your hazards. Visit the library at the end of

this guide for more information on specific hazards, contacts, or

additional resources to help you profile your hazards.

____

When you have completed all of your hazard profiles

Go to Step 3

where you will inventory the assets in your planning area that can

be damaged by the hazard events you profile.

____

Level of Risk

If your planning team determines that the level of acceptable risk is different than the

level identified by the suggested hazard event in this guide, it may

be necessary to revise your risk assessment by profiling a lesser or greater

hazard event. For example, you may

choose to evaluate an area greater than

the 100-year flood elevation established

on the FIRM by assessing the 100-year

flood elevation plus one additional foot (or

other amount).

Practical

Considerations

when Using Maps

Hazard profile maps can

range from simple traced maps to elaborate GIS productions. Both renditions will

illustrate your hazard prone areas and will

assist you in the next step of taking inventory of the elements that can be damaged.

Often the individual hazard maps to be

used are at different scales. This may require an enlargement or reduction to the

scale of the base map selected. Use of

controlled photographic or computer mapping methods makes this process easy

and accurate.

Copies of maps can be made on large

format copying machines used by most

reprographic companies. Maps also can

be professionally photographed and

transferred onto your base map.
Version 1.0 August 2001 2-5

profile hazard events 2

You may want to recommend that

communities use a consistent base

map, particularly if your state has already developed

mapping at a suitable scale that can be used locally

and covers the entire state. For example, a statewide

Geographic Information System (GIS) would allow you to easily

incorporate local information into state planning efforts.

As you proceed, keep in mind you will want to incorporate the

results of individual communities' risk assessments into your own.

This will give you more details on hazards and risks throughout

the state. You may want to provide guidance to communities on

the level of detail and return frequencies to use in local risk assessments in order to produce a uniformly consistent state risk

assessment. You may also want to fill in the gaps for the areas of

the state or communities that do not have local risk assessments.

You will also need to decide whether you will conduct the loss

estimation state properties or request that local governments do

this as part of community-level planning. Either way, you should

make sure communities are aware how to treat state-owned facilities in their loss estimation.

Base Map Options

Different maps have different

advantages and limitations.

Some alternatives (listed in order of increasing price and utility) include:

Road maps. There are usually detailed

road maps available for areas in and

around urban centers. It is important to

verify the date the map was produced

because it may be outdated and inaccurate. Also, although the street network will be depicted, it is unlikely that

buildings will show up on the map.

Therefore, you'll have to convert the

map for use in risk assessment.

USGS Topographic Maps. Maps

showing topographic relief are available

for the entire country at 1:24,000 scale

(see Scale and Coverage below) from

the United States Geological Survey

(USGS). Some structures are indicated although not in great detail. Most

roads are shown but few are identified.

These maps can be obtained via the

Internet at http://mapping.usgs.gov/

mac/nimamaps/topo.html, or in hard

copy from USGS by calling 1-888-

ASK-USGS. These maps will have to

be converted for use as a base map,

just like the road maps. Like road maps,

it is important to verify the date the mapping was completed to determine the

relative accuracy of the mapped information.

USGS Digital Orthophoto Quarter

Quad (DOQQ)

A DOQQ is a computer generated image

of an aerial photograph in which displacements caused by camera orientation and

terrain have been removed.These products combine the image characteristics

of a photograph with the geometric qualities of a map and can be used in numerous GIS applications either alone or in

combination with other digital data.

For more information on the USGS digital

orthophoto program and DOQQ products

visit the USGS Web site at http://

mapping.usgs.gov/www/ndop/ or visit the

National Mapping Information Web page

at http://mapping.usgs.gov/index.html

Topographic and/or Planimetric

Maps from other agencies. Local

agencies such as county or regional

planning commissions often have

maps. If there have been major roadwork or infrastructure projects within

recent years, public works and transportation departments may have detailed maps that cover all or part of an

area of interest.

Aerial Topographic and/or Planimetric Maps. Communities can get new

aerial topographic (indicating all built

features as well as contour lines that

represent the physical shape of the

land) or planimetric (indicating built

features only) from companies that

specialize in aerial photography and

photogrammetry. These days, this

type of map is always produced in

digital as well as reproducible formats.

Topographic maps are usually more

expensive but may be quite useful

for other efforts including follow-up

planning for mitigation projects identified later in the planning process. At

a minimum, aerial photographs are

useful in basic planning efforts as they

provide a reliable, recognizable representation of the assets of the community at a reasonable cost.

Field Surveys. In unusual circumstances, it may be practical to have

field surveys done. However, for areas of any significant size, this option

is more expensive than aerial topographic and planimetric maps and

may not yield significantly better information for the mitigation planning

efforts.

Scale and Coverage

Scale determines the area covered on

the map. The scale is a proportion used

in determining a dimensional relationship, which is the ratio of the distance between two points on a map and the actual

distance between the two points on the

earth's surface. For example, the scale

1:500,000 means that one centimeter on

the map equals 500,000 centimeters (or

5,000 meters or 5 kilometers) on the

ground. Small-scale maps show less detail for a large area. Smaller scales are

more common for regional (1:500,000

through 1:50,000), and community plans

(1:24,000 through 1:12,000).

The scale selected will depend upon the

map's purpose. There are no best scales,

only more appropriate ones to coincide

with planning requirements. Consider the

following scales for example:

World: 1:30,000,000

Continent: 1:5,000,000 to

1:2,000,000

Region: 1:500,000 to 1:50,000

Community or settlement:

1:24,000 to 1:12,000

Building sites: 1:10,000 to 1:2,500

The level of detail, the hazards shown, and

the format of a risk assessment map can

range widely depending on the scale you

choose. The scale used for a risk assessment is dependent upon not only the hazard information to be shown but also upon

the scale of the base map. If a choice of

scales is available, then the following factors become important in making the selection:

Number of hazards to be shown.

Hazard characteristics to be

shown.

Range of relative severity of hazards to be shown.

Area to be covered.

Use of the map in conjunction with

other planning documents.

Function of the map, for example,

whether it is to be an index or detail map.
2-6 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Map Symbols

Mapped hazard areas can show various degrees of risk (e.g., seismic risk) or can identify a zone where risk is present

(e.g., a floodplain). Map symbols represent reality by conveying a sense of the hazard. Symbols that represent hazard

characteristics are selected for their legibility, clarity, and/or map production characteristics. There are three distinct map

symbols: points, lines, and areas. The maps below depict characteristics of Hurricane Georges using points, lines, and areas.

Points can be used to show location of

fire and police stations, hospitals, and

emergency shelters, as well as points

of impact from hurricanes, epicenters

of earthquakes or locations of specific

flood frequencies.

Advanced computer

programs have been developed for displaying and analyzing hazard identification

data. Three of the most common computer programs used for hazard

mapping are FEMA's Hazards U.S.

(HAZUS), Geographic Information Systems (GIS), and Computer Aided Design

& Drafting (CADD).

HAZUS

HAZUS contains an extensive inventory

of data that communities can use and

build upon as a loss estimation tool.

HAZUS is currently being expanded into

a multi-hazard methodology with new

models for estimating potential losses from

wind (hurricanes, thunderstorms, tornadoes, and extra-tropical cyclones) and

flood (riverine and coastal) hazards.

HAZUS is a flexible tool that has potential

for use in risk assessment, response and

recovery, and awareness and preparedness programs.

GIS

GIS is a computer-based tool for mapping

and analyzing physical elements and

events that occur on earth. GIS is a database that relates detailed information directly to a geographical area for mapping

and analysis purposes. Software for GIS

is available from many distributors.

ArcView® and MapInfo® are two of the

most commonly used sources of GIS software.

GIS allows users to overlay different kinds

of data to determine relationships among

them. Maps produced with GIS can help

to explain hazard events, predict outcomes, visualize scenarios, and plan

strategies. Some communities and regional planning authorities maintain GIS

databases for planning land uses and

managing utilities. GIS can map hazard

areas and present hazard identification

information, allowing the user to compare

these areas with existing land uses. GIS

also allows the user to:

Import geographic data such as

maps;

Manipulate geographic data and

update community zoning maps;

Store and analyze attributes associated with geographic data;

Perform queries and analyses to

retrieve data (for example, show all

child care centers within five miles

of a fire station); and

Display results as maps or graphs.

CADD

CADD is a computer system that allows

users to perform drawing and design

tasks, enabling quick and accurate electronic drawings. There are hundreds of

CADD programs available in the CADD

industry today, furnishing 2D drawings, 3D

drawings, topographic base maps, site

plans, and profiles/cross sections. Detailed hazard maps in a variety of dimensions can be made using CADD products

on a computer.

Digitizing

Digitizing maps is the process of converting points, lines and area boundaries

shown on maps into x, y coordinates (e.g.

latitude and longitude, universal transverse

mercator (UTM) or table coordinates). If

your community does not already have

this capability, you should contact local

civil engineering or land surveying companies to investigate opportunities for contracting this work.

Lines can be used to separate areas

of landslide frequency, to represent

earthquake intensity, or to show tracks

of storms, fault rupture, or tsunamis.

Areas can be used to show the extent

of certain hazard conditions, such as

flooding as well as erosion and wildfire

zones.
profile hazard events 2

Version 1.0 August 2001 2-7

Data Availability

If a particular hazard map is not

available for your planning area,

you can create one using a variety of methods depending on the level of

detail and accuracy required. The following examples range from simplest to the

most complex.

Historical hazard event. The chosen

event will determine the physical extent

of the hazard and the severity. This

method will provide a “snapshot” of one

potential event. Later in this step, the hazard-specific sections that follow offer suggestions of how to gather information for

historic hazard events.

Detailed hazard profile. You can create

a detailed hazard profile by researching:

how likely it is that hazard will impact the area (probability);

how severe the hazard will be

(magnitude);

where hazards will affect the community or state (geographic extent);

and

conditions in the community that

may increase or reduce the effects

of hazards.

These elements are closely related, and

are often combined in expressions linking probability (or frequency) and magnitude (or extent). Some examples of the

types of factors that can exacerbate (increase) or mitigate (reduce) hazard effects are:

topography (for most hazards)

soil characteristics (earthquakes

and landslides)

soil saturation (floods and landslides)

presence of fuel load (wildfires)

presence of development in the

hazard area (floods)

existence of hazardous materials

facilities in or near hazard zones

(for all hazards)

Some of the factors are aspects of the

planning area over which people have

some control. For example, while you cannot control the duration of a hurricane, you

can decide not to build on or near steep

slopes. The hazard-specific sections that

follow offer suggestions of how to gather

information to conduct a detailed hazard

profile, and the library in Appendix B offers suggestion of where to find more information on specific hazards. These

factors will become important when planning the mitigation actions to protect your

community or state from natural hazards

in phase three of the natural hazard mitigation planning process.

Engineering study. Hydraulic engineers

calculate flood elevations through stream

gauge data and information on drainage

area, rainfall potential, characteristics of

the source of flooding (usually a river or

stream), and soil saturation. The hazardspecific sections that follow offer suggestions of various computer modeling

programs, as well as information about

who you should contact for additional help.

Data Limitation

Data about what’s happened in the past

is often used to estimate what’s likely to

happen in the future. For example,

chances are that “tornado alley” in the midwest, will experience more tornadoes this

year than other parts of the United States.

This assumption is simply based on the

fact that tornadoes have often impacted

that area in the past. The same is true in a

small town whose main street has flooded

numerous times in the past. However,

there’s a big difference between a particular street being flooded and an entire state

being impacted by tornadoes. There are a

number of site-specific characteristics that

determine flood potential. On the other

hand, a state that has experienced an average of 100 tornadoes each year for the

last 30 years does not mean that a tornado will hit any particular point in the state

next year.
2-8 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

The Hazardville Post

Vol. CXI No. 158 Thursday, June 7, 2001

THORR Profiles Hazardville's Hazards

(Part 2 of a 4 Part Series on the Risk Assessment Process)

[Hazardville, EM] In April, the

Hazardville Post reported the ongoing work of the Town of Hazardville

Organization for Risk Reduction

(THORR). THORR recently completed its hazard research and has developed a series of hazard profiles that

represent the next big step in describing the problems.

Joe Norris, lead planner of the

task force, emphasized, "Our motto,

'A Small Town with Big Problems' is

certainly accurate when it comes to

natural hazards, but our recent efforts

of identifying and profiling the hazards will help us deal with them effectively in the future." Norris said

that a host of hazards, including floods,

earthquakes, tsunamis, tornadoes, hurricanes, landslides, and wildfires, pose

potential threats to the Town of

Hazardville. THORR presented its

hazard profiles at last night's Board of

Supervisors meeting.

Mary Tremble, director of the

Hazardville Emergency Management

Agency (HEMA) and head of the

Earthquake, Tsunami and Landslide

Workgroup, revealed that Hazardville

has a moderate earthquake threat. "After learning about our seismic potential from the state geologist, the

Workgroup contacted Emergency

State University's Geology Department for more information on seismicity. Using maps produced by the

U.S. Geological Survey, we found that

the entire town is within a seismic

zone that has a 10% chance of exceeding 0.3g in 50 years." The %g refers

to the percent of acceleration due to

gravity and is used to measure the

strength of ground movements.

For Hazardville, that generally

means that an earthquake of that

size could cause moderate to severe

damage according to Tremble. For

example, it could cause moderate

damage to structures with un-reinforced masonry chimneys or severe

damage to poorly constructed

buildings. A large off-shore earthquake could also cause a tsunami

that could impact up to one-mile inland of the Hazardville coastline

within 15 minutes of the quake.

Tremble reported that the biggest concern for the Workgroup is

the area of town that is susceptible

to landslides. Several landslides

have been recorded on the bluffs

following heavy rains. These areas

are susceptible to slides mostly because of ground saturation but also

present a danger when earthquakes

occur because of the steep slopes,

Tremble said. Hazardville has three

landslide zones. “The areas of past

landslides are shown as high hazard

areas,” Ms. Tremble said. “The

moderate hazard area is north of

Raging River and includes areas

with steep slopes and unstable

soils.”

Mr. David Waters, head of the

Flood and Hurricane Workgroup,

explained Hazardville's flood risk.

Waters, who is also the town's

Floodplain Manager, explained that

Hazardville's Flood Insurance Rate

Map (FIRM) shows the 100-year

floodplain (areas with a 1% chance

of flooding each year) in the coastal

region to the south and in the vicin-

(continued on page 2-9)

Raging River

Hazardville Tsunami Hazard Profile

Tsunami Inundation Areas
profile hazard events 2

Version 1.0 August 2001 2-9

ity bordering Raging River in the

northern part of town. The

coastal region is designated as

AE and VE zones, meaning that

floods will have wave action and

will travel quickly. A map of the

town with its flood hazard zones

illustrates that floods pose a

threat to a significant portion of

the community.

Ms. Wendy Soot, head of the

Tornadoes and Wildfires

Workgroup, cautioned that

Hazardville is also susceptible to

tornadoes. "Hazardville is located

in a 200 mph wind zone, which

means we could experience a

severe (F3) tornado. A tornado

of this severity could remove

roofs, knock over walls, and even

overturn cars and trains."

Soot, who is also the town's

Fire Marshal, added that Hazardville has

four wildfire zones. "We have an extreme

and high wildfire hazard area on the

northern edge of town due to the steep

topography and heavy fuel of the forest,"

(continued from page 2-8)

Ms. Soot said. "The area of town south

of Raging River is considered a moderate and high wildfire hazard area, due to

the light fuel and proximity to the forest.

When asked about the professional

look of the maps, Norris responded that

all mapping was done using the town's

own resources. "In fact," he explained,

"the base was traced from a USGS map

by the Hazardville Planning Office." The

hazard profiles were compiled from

various sources including soil maps, topography maps, and storm surge maps.

A map specialist from the transportation

department helped us trace the hazard

profiles on to our base map. Some of

the maps had to be reduced or enlarged

on a copy machine to produce the same

scale as the base map.

Norris expects the risk assessment

process to continue to be successful.

He credited the hard work of THORR

members and the state and federal government workers who have assisted

them. "This has been and will continue

to be a truly cooperative effort," he said.

Fuel Model

C 41-60%

slopes

Fuel Model

A&L <40%

slope

No/Light

Fuel <40%

slope

Low Hazard

Moderate Hazard

High Hazard

Extreme Hazard

Fuel Model

I,J&K <40%

slope

Fuel Model

I&J 41-60%

slopes

Fuel Model

F <40% slope

E

M

H

L
2-10 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Floods

At the very least, you

should research past or historic flood events. You can

use old watermarks and eyewitness accounts to delineate

the approximate flood boundaries and

depths of flooding on your base map, or

especially if there is not a FIRM or Q3

available for your community. Contact

your state NFIP coordinator for more information on flooding in your area. In addition, the USGS, U.S. Army Corps of

Engineers, or a civil engineer skilled in

hydraulic analysis can help you conduct

a flood study.

Task B. Obtain flood hazard event profile information.

The best source of local flood hazard information is the Flood

Insurance Study (FIS) developed under the National Flood Insurance Program (NFIP) administered by FEMA. An FIS contains a

Flood Insurance Rate Map (FIRM), which is an official map of a

community that shows areas at risk from flooding from the base

flood (see page 2-12 for more information on floods). Another

element of the FIS is a graph, also known as a flood profile, which

shows potential flood elevations

plotted along the waterways. This

information will help you delineate the boundaries of the floodplain in your planning area.

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The following is the system FEMA uses on the FIRMs to categorize different floodplain areas.

1. Get a copy of your FIRM.

By using a copy of the FIRM, you

will evaluate the 100-year flood (a

flood that has a 1 percent chance

of occurring in any one year).

Copies of FIRMs can be requested by calling the FEMA Map

Service Center at

1.800.358.9616, on the Internet

at http://www.fema.gov/maps,

or by contacting a FEMA Regional Office. Additionally, the

NFIP's Guide to Flood Maps is
profile hazard events 2

Version 1.0 August 2001 2-11

FEMA uses two methods to

make flood map changes.

The first is to actually change the map

and publish new copies. The other

method is to issue a letter that describes

the map change. There are two types of

letters indicating map changes:

LOMR – Letter of Map Revision

LOMA – Letter of Map Amendment

These letters officially amend

or revise the effective NFIP

map. Contact your FEMA regional office for more information on map changes.

Most flood information is provided on a community-wide scale. Rather

than compiling a FIRM for

each community in your

state, you can use Q3s. The Q3 maps

are available on the state-specific supplemental data CD ROMs for use with

FEMA's GIS-based HAZUS Loss Estimation software program.

You should also be prepared to assist

communities with obtaining flood mapping, and understanding the information

presented on FIRMs.

(continued on page 2-14)

available on the web at http://msc.fema.gov/MSC/hardcopy.

htm, and flood risk and map information is available at

http://www.fema.gov/nfip/fmapinfo.htm.

FEMA is currently involved in converting FIRMs to digital format

(DFIRM). The DFIRM product will be designed to allow for the

creation of interactive multi-hazard digital maps that can be used

on a personal computer using GIS.

Digital Q3 flood data is available for 1,200 counties in CD-ROM

format. The Q3s are digital representations of certain features of

FIRMs and are intended for use with desktop mapping and GIS

technology. The Q3s are used for hazard mitigation planning,

floodplain management, land-use planning, natural resource and

environmental analysis, and insurance target marketing. They are

designed to provide the general location of the Special Flood

Hazard Area (SFHA). The main differences between the Q3s and

the official paper FIRMs is that the Q3s do not include the following:

 hydrographic features (streams and rivers, lake and

coastal shorelines);

 base flood elevations;

 cross-section lines;

 roads, road names, or address ranges; and

 locations, elevations and descriptions of benchmarks and

elevation reference marks.

The Digital Q3 Flood Data and DFIRMs are also available from the

FEMA Map Service Center, in addition, the Q3 maps are available

on the FEMA HAZUS CD.

If you participate in the NFIP you should have FIRMs locally.

Contact your NFIP coordinator or floodplain manager, usually

located in the planning, building, engineering, or natural resources

department, or your state NFIP coordinator for copies of your FIRM

or to help you identify areas that are prone to flooding. Your state

NFIP coordinator or state floodplain manager can be found at

http://www.floods.org/stcoor.html.

2. Verify that the FIRM is up-to-date and complete.

No map is perfect and floodplains change due to a number of

reasons. From time to time, FEMA, communities or individuals may

find it necessary for a FIRM to be updated, corrected, or changed.

Review the FIRM to determine whether any of the following circumstances apply to your planning area:
2-12 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

are shown on the floodway map and people often confuse the white floodway with the white area representing

land that is free from flooding. FIS reports published since

1986 have corrected this problem by delineating the floodways as diagonally hatched areas on the FIRMs.

What is a flood?

A flood is a natural event for rivers and streams. Excess water from snowmelt, rainfall, or storm surge accumulates and overflows onto the banks and adjacent

floodplains. Floodplains are lowlands, adjacent to rivers, lakes, and oceans that are subject to recurring floods. Hundreds of floods occur each year, making it one

of the most common hazards in all 50 states

and U.S. territories. Floods kill an average of

150 people a year nationwide. They can occur

at any time of the year, in any part of the country, and at any time of day or night. Floodplains

in the U.S. are home to over nine million households. Most injuries and deaths occur when

people are swept away by flood currents, and

most property damage results from inundation

by sediment-filled water.

Several factors determine the severity of floods,

including rainfall intensity (or other water

source) and duration. A large amount of rainfall

over a short time span can result in flash flood

conditions. A small amount of rain can also result in floods in locations where the soil is saturated from a previous wet period or if the rain is

concentrated in an area of impermeable surfaces such as large parking lots, paved roadways, or other impervious developed areas.

Topography and ground cover are also contributing factors for

floods. Water runoff is greater in areas with steep slopes and little

or no vegetative ground cover.

Frequency of inundation depends on the climate, soil, and channel

slope. In regions where substantial precipitation occurs in a particular season each year, or in regions where annual flooding is

derived principally from snowmelt, the floodplains may be inundated nearly every year. In regions without extended periods of

below-freezing temperatures, floods usually occur in the season

of highest precipitation. In areas where flooding is caused by melting snow, and occasionally compounded by rainfall, the flood season is spring or early summer.

Fortunately, most of the known floodplains in the United States

have been mapped by FEMA, which administers the NFIP. When

a flood study is completed for the NFIP, the information and maps

are assembled into a Flood Insurance Study (FIS). An FIS is a

compilation and presentation of flood risk data for specific watercourses, lakes, and coastal flood hazard areas within a community and includes causes of flooding.

The FIS report and associated maps delineate Special Flood Hazard Areas (SFHAs), designate flood risk zones, and establish base

flood elevations (BFEs), based on the flood that has a 1% chance

of occurring annually, or the 100-year flood. The study may have

three components:

The FIS – Flood Insurance Study text;

The FIRM – Flood Insurance Rate Map; and

A separate Flood Boundary and Floodway Map (FBFM)

that was issued as a component of the FIS for each community studied prior to 1986. No BFE or flood zone names

The 100-year flood designation applies to the area that has a

1 percent chance, on average, of flooding in any given year.

However, a 100-year flood could occur two years in a row, or

once every 10 years. The 100-year flood is also referred to as

the base flood. The base flood is the standard that has been

adopted for the NFIP. It is a national standard that represents a

compromise between minor floods and the greatest flood likely

to occur in a given area and provides a useful benchmark.

Base Flood Elevation (BFE), as shown on the FIRM, is the

elevation of the water surface resulting from a flood that has a

1% chance of occurring in any given year.

The BFE is the height of the base flood, usually in feet, in relation to the National Geodetic Vertical Datum (NGVD) of 1929,

the North American Vertical Datum (NAVD) of 1988, or other

datum referenced in the FIS report.

Special Flood Hazard Area (SFHA) is the shaded area on a

FIRM that identifies an area that has a 1% chance of being flooded

in any given year (100-year floodplain).

FIRMs show different floodplains with different zone designations. These are primarily for insurance rating purposes, but the

zone differentiation can be very helpful for other floodplain planning purposes. The more common zones were listed in the table

on page 2-10.

Floodway is the stream channel and that portion of the adjacent floodplain that must remain open to permit passage of the

base flood without raising the water surface elevation by more

than one foot.

NGVD – National Geodetic Vertical Datum of 1929, the national datum used by the NFIP. NGVD is based on mean sea

level. It was known formerly as the "Mean Sea Level Datum of

1929 (MSL)." NAVD 88 = North American Vertical Datum of

1988 is being phased in.
Version 1.0 August 2001 2-13

profile hazard events 2

It's important to recognize that there

is actually a range of floods, other than

just the 100-year flood, that could happen within your

planning area. For example, a house located close to

a flood source might experience some level of flooding every 5 to 10 years. The level or depth of flooding is determined by the probability.

The probability of a flood is based on a statistical chance of a

particular size flood (expressed as cubic feet per second of water flow) occurring in any given year. The annual flood is usually

considered the single greatest event expected to occur in any

given year. The percent annual chance of floods is estimated

based on watershed and climatic characteristics or watershed

models, water surface elevations, and hydraulic models that reflect topographic characteristics.

The risk created by the 100-year flood would be much greater

than the risk from the annual flood based on the amount of damages each event produces – once. But the annual flood would

Conditions that may exacerbate or

mitigate the effects of floods

The following factors will affect the severity of a flood:

Impermeable Surfaces: Excessive amounts of

paved areas or other surfaces upstream or in the community can increase the amount and rate of water runoff. Development affects the runoff of stormwater and snowmelt

when buildings and parking lots replace the natural vegetation, which normally would absorb water. When rain falls

in an undeveloped area, as much as 90 percent of it will

infiltrate the ground; in a highly developed area, as much

as 90 percent of it will run off.

Steeply sloped watersheds: In hilly and mountainous

areas, a flood may occur minutes after a heavy rain. These

flash floods allow little or no warning time and are characterized by high velocities.

Constrictions: Re-grading or filling within or on the edge

of floodplains obstructs flood flows, backing up floodwaters onto upstream and adjacent

properties. It also reduces the

floodplain's ability to store excess

water, sending more water downstream and causing floods to rise

to higher levels. This also increases floodwater’s velocity

downstream of the constriction.

Obstructions: Bridges, culverts

and other obstructions can block

flood flow and trap debris, causing

increased flooding upstream and

increased velocity downstream.

Debris: Debris from the watershed, such as trees, rocks, and

parts of damaged buildings, increases the hazard posed by moving water. Moving water will float,

drag or roll objects, which then act

occur much more frequently and over time may in fact produce a

much greater risk to the structure than the 100-year flood.

Flood frequencies can be determined by plotting a graph of the

size of all known floods for an area and determining how often

floods of a particular size may occur. In addition, hydrologic and

hydraulic data gathered from rivers and streams is a valuable

but time-consuming effort to calculate flood frequencies. If at least

20 years worth of data are available through stream gauging,

models can be used to determine the statistical frequency of given

flood events.

The USGS maintains river gauge records. Historical and current

river gauge information can be observed at its Website at http://

water.usgs.gov. Some local agencies may also have gauge

records.

The process of conducting a more rigorous risk assessment to

include all of the possible hazard events will be discussed in the

“how-to” for the third phase of the Natural Hazard Mitigation Planning Process, “Develop a Mitigation Plan.”

as battering rams that can knock holes in walls and further exacerbate the effects of debris.

Contamination: Few floods have clear floodwater, and

the water will pick up whatever was on the ground within

the floodplain, such as soil, road oil, farm and lawn chemicals, and animal waste. In addition, if a wastewater treatment plant was inundated, the floodwaters will likely include untreated sewage. Contamination is also caused by

the presence of hazardous material storage in the floodplain and in the community, as well as upstream from the

community.

Soil saturation: Rainfall in areas already saturated with

water will increase the runoff.

Velocity: Flood velocity is the speed of moving water, measured in feet per second. High velocities (greater than 5

feet per second) can erode stream banks, lift buildings off

their foundations, and scour away soils around bridge supports and buildings.
2-14 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

As you map your flood

hazard areas and plan for

mitigation of flood hazards, consider applying for credit for Community Floodplain Management

Planning under FEMA's Community Rating

System (CRS). If you are not currently enrolled in CRS, contact your state floodplain

manager.

If you live in a community that

could be affected if an upstream dam were overtopped

or breached, contact your state dam

safety official identified on the Website of

the Association of State Dam Safety Officials (ASDSO), at http://crunch.tec.army.mil/

nid/webpages/nid.cfm and click on "State

Links". The state official will assist you in determining whether there are any large dams

that could flood your community if breached

or overtopped. There are thousands of significant and high-hazard potential dams in

the U.S. About 60 percent have Emergency

Action Plans, which delineate the

inundation area if the dam fails or

is overtopped. The inundation areas are usually much larger than

the 100-year floodplain.

(continued from page 2-11)

 Significant construction has occurred within the

already identified floodplains on your FIRM.

 Upstream communities have had significant development since the FIRM was published.

 There has been a flood for which inundation pattern

indicates that the FIRM boundaries are no longer

accurate.

 A major flood control project has been completed

within your community, or upstream of your

community.

 Changes in topography in or adjacent to existing

mapped floodplains.

If the area you're considering is not within the 100-year floodplain, you may elect to concentrate on other hazards because

your risk is, by definition, relatively small. However, you may still

have flood risks that arise from one or more of the following,

which are not shown on the FIRM:

 Drainage areas of less than one square mile;

 Sewer backup;

 Drainage system backup;

 Dam breaches; and

 Stormwater runoff problems.

Task C. Record your hazard event profile information.

1. Transfer the boundaries from your FIRM onto your base map.

2. Record the base flood elevations onto your base map.

____

Go to the next hazard on your list to

profile

or if you are finished with all your hazard profiles

Go to Step 3

____
Version 1.0 August 2001 2-15

profile hazard events 2

Task B. Obtain earthquake hazard event profile

information.

1. Go to the http://geohazards.cr.usgs.gov Website.

Earthquakes

Seismic hazardmaps are available for the whole country, as well as regional maps of Alaska, California, Nevada, and the Central and Eastern United

States. For California, the USGS and the

California Division of Mines and Geology

have earthquake fault zone maps and

seismic hazard zone maps. You can order these maps by calling

USGS at 1-888-ASK-USGS.

You should also contact your

state geologist for additional

hazard information.

The map shows the national Peak Ground Acceleration (PGA)

values for the United States with a 10% chance of being exceeded

over 50 years. This is a common earthquake measurement that

shows three things: the geographic area affected (all colored areas

on the map), the probability of an earthquake of each given level

of severity (10% chance in 50 years), and the severity (the PGA is

indicated by color).

2. Locate your planning area on the map.

You can also generate maps based on zip codes or longitude and

latitude by following the directions on the Website.

3. Determine your Peak Ground Acceleration.

Determine the PGA zone(s) in which your planning area is located.

This is done by identifying the color associated with your planning

area and correlating it with the color key located on the map. Large

planning areas may be located in more than one zone.

Peak ground acceleration

(PGA) is a measure of the strength of

ground movements. The PGA measures

the rate in change of motion relative to

the established rate of acceleration due

to gravity (g) (980 cm/sec/sec). For example, in an earthquake with an acceleration of the ground surface of 244 cm/

sec/sec, the PGA or rate in change of

motion is 25%g where:

%g = Ground Surface Acceleration / Rate of

Acceleration due to

Gravity;

%g = 244 cm / sec/ sec/ 980

cm / sec / sec; and

%g = 25%

Source: http.geohazards.cr.usgs.gov/eq/pubmaps/US.pga.050.map.gif
2-16 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

What is an Earthquake?

Earthquakes are one of nature's most damaging hazards. An earthquake

is a sudden motion or trembling that is caused by a release of strain

accumulated within or along the edge of Earth's tectonic plates. The severity of these effects is dependent on the amount of energy released

from the fault or epicenter. The effects of an earthquake can be felt far beyond the

site of its occurrence. They usually occur without warning and after just a few seconds can cause massive damage and extensive casualties. Common effects of

earthquakes are ground motion and shaking, surface fault ruptures, and ground

failure.

Earthquakes are more widespread than is often realized. The area of greatest seismic activity in the United States is along the Pacific Coast in California and Alaska,

but as many as 40 states can be characterized as having at least moderate earthquake risk. For example, seismic activity has been recorded in Boston, Massachusetts; New Madrid, Missouri; and Charleston, South Carolina, places not typically

thought of as earthquake zones. Areas prone to earthquakes are relatively easy to

identify in the Western United States based on known geologic formations; however, predicting exactly when and where earthquakes will occur is very difficult

everywhere.

There are several common measures of earthquakes. These include Richter Magnitude, Modified Mercalli Intensity (MMI), Moment Magnitude and Peak Ground Acceleration (PGA), among others. For this guide, we're using PGA for measuring

earthquake hazard.

Acceleration: One way to express an earthquake's severity is to compare its acceleration to the normal acceleration due to gravity. If you're standing on the surface

of the earth and drop an object (ignoring wind resistance), it will fall toward the earth

faster and faster, until it reaches terminal velocity. This principle is known as acceleration and represents the rate at which speed is increasing. The acceleration due

to gravity is often called "g", a term you may have heard associated with roller

coasters, rockets, or even stock car racing. The acceleration due to gravity at the

earth's surface is 9.8 meters (980 centimeters) per second squared. That means

that every second that something falls toward the surface of earth its velocity increases by 9.8 meters per second. A 100% g earthquake is very severe.

An analogy would be if you floor your car's gas pedal and your groceries get

smashed against the back of the trunk. The quicker you press on the gas, the more

eggs are likely to get broken. That's because the quick acceleration caused the

contents of your trunk to shift rapidly and violently, not slowly and smoothly. In fact,

the eggs might not have moved at all if you had sped up slowly. The same thing is

true in an earthquake. If ground acceleration is rapid, more things tend to break than

if the shaking is relatively slow, even if the ground moves the same distance.

Earthquake Motion: The variables that characterize earthquakes are ground motion, surface faulting, ground failure, and seismic activity. Ground motion is the

vibration or shaking of the ground during an earthquake. When a fault ruptures,

seismic waves radiate, causing the ground to vibrate. The severity of the vibration

increases with the amount of energy released and decreases with distance from

the causative fault or epicenter, but soft soils can further amplify ground motions.

Surface faulting is the differential movement of two sides of a fracture – in other

words, the location where the ground breaks apart. The length, width, and displacement of the ground characterize surface faults.

Liquefaction is the phenomenon that occurs when ground shaking causes loose

soils to lose strength and act like viscous fluid. Liquefaction causes two types of

ground failure: lateral spread and loss of bearing strength. Lateral spreads develop on gentle slopes and entail the sidelong movement of large masses of soil as

an underlying layer liquefies. Loss of bearing strength results when the soil supporting structures liquefies. This can cause structures to tip and topple.

Definition sketch for earthquake.
Version 1.0 August 2001 2-17

profile hazard events 2

Task C. Record your hazard event profile

information.

1. Record your PGA value.

If you are located in only one PGA zone, note that

zone on Step 2 Worksheet and go to the bottom of

this page; otherwise, continue with part 2 of this

task.

2. Print, download, or order your PGA map.

If you are located in more than one PGA zone, you

will need a copy of your PGA map. Maps can be

printed, downloaded or ordered from the USGS

Website.

3. Transfer the boundary of your PGA zones onto your

base map.

4. Record the PGA value(s) on your worksheet.

____

Go to the next hazard on your

list to profile

or if you are finished with all your hazard profiles,

Go to Step 3

____

The HAZUS Loss Estimation Tool

FEMA developed a standardized, nationally applicable earthquake loss estimation methodology.

This methodology is implemented with PC-based

software called HAZUS (Hazards U.S.),which

runs on a Geographic Information System (GIS) platform.

The HAZUS loss estimation methodology is a software program that uses mathematical formulas and information about

building stock, local geology and the location and size of

potential earthquakes, economic data, and other information to estimate losses from a potential earthquake. HAZUS

is capable of using two separate GIS systems (MapInfo®

or ArcView®) to map and display ground shaking, the pattern of building damage, and demographic information about

a community.

Once the location and size of a hypothetical earthquake are

identified, HAZUS will estimate the violence of ground shaking, the number of buildings damaged, the number of casualties, the amount of damage to transportation systems,

disruption to the electrical and water utilities, the number of

people displaced from their homes, and the estimated cost

of repairing projected damage and other effects.

Level 1 – All of the information needed to produce a

rough estimate of losses from an earthquake is included in the HAZUS software. This is data from national databases and describes in general terms the

geology of the region and the building inventory and

economic structure of the community. The default data

that HAZUS includes are used to provide a basic estimate of losses and are useful in mitigation planning.

Level 2 – More accurate estimates of losses require

more detailed information about the community. To produce a Level 2 estimate of losses, detailed information will be required about local geology, an inventory

of buildings in the community, and data about utilities

and transportation systems. Assistance from

geotechnical and structural engineers may be necessary for this analysis, as well as a GIS specialist to

add the detailed information into the HAZUS model.

Level 3 – The most accurate estimate of loss will require detailed engineering and geotechnical input to

customize the methodology to the specific conditions

of the community.

While Level 1 HAZUS studies can typically be carried out

by local government emergency services or planning staff,

the assistance of structural engineers, geologists and GIS

specialists is generally needed for Level 2 and Level 3 estimates.

Unlike communities, states may have many

different PGA zones. Your proximity to faults and soil

and subsurface characteristics all affect the level of

earthquake hazard. Here it is also important to note

the pattern or gradation of seismic characteristics

across the state.
2-18 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

What is a Tsunami?

A tsunami is a series of long waves generated in the ocean by a sudden

displacement of a large volume of water. Underwater earthquakes, landslides,

volcanic eruptions, meteor impacts, or onshore slope failures can cause this

displacement. Most tsunamis originate in the Pacific "Ring of Fire," the area of the Pacific

bounded by the eastern coasts of Asia and Australia and the western coasts of North

America and South America that is the most active seismic feature on earth. Tsunami

waves can travel at speeds averaging 450 to 600 miles per hour. As a tsunami nears the

coastline, its speed diminishes, its wavelength decreases, and its height increases greatly.

Unusual heights have been known to be over 100 feet high. However, waves that are 10

to 20 feet high can be very destructive and cause many deaths and injuries.

After a major earthquake or other tsunami-inducing activity occurs, a tsunami could

reach the shore within a few minutes. From the source of the tsunami-generating event,

waves travel outward in all directions in ripples. As these waves approach coastal areas, the time between successive wave crests varies from 5 to 90 minutes. The first

wave is usually not the largest in the series of waves, nor is it the most significant. One

coastal community may experience no damaging waves while another may experience

destructive deadly waves. Some low-lying areas could experience severe inland inundation of water and deposition of debris of more than 1000 feet inland.

Along the West Coast, the Cascadia Subduction Zone threatens California, Oregon,

and Washington with devastating local tsunamis. Earthquakes of Richter scale magnitude of 8 or more have happened in the zone, and there is a 35 percent chance that an

earthquake of this magnitude could occur before 2045 (estimated between the years

1995 and 2045). The Alaska and Aleutian Seismic Zone that threatens Alaska has a

predicted occurrence (84 percent probability between 1988 to 2008) of an earthquake

with magnitude greater than 7.4 in Alaska. If an earthquake of this magnitude occurs,

Alaska's coastlines can be expected to flood within 15 minutes.

Task B. Obtain tsunami

hazard event profile

information.

Get a copy of your tsunami

inundation zone map.

Tsunami inundation zone

maps show low-lying areas that

could be affected by tsunamis.

Communities can obtain statelevel inundation maps and

other information about

tsunamis from:

 West Coast/Alaska

Tsunami Warning

Center of NOAA/

NWS by calling

907.745.4212 or by

writing 910 S.

Felton Street,

Palmer AK 99645-

6552.

 Pacific Tsunami

Warning Center in

Hawaii at

808.689.8207 or 91-

270 Fort Weaver

Road, Ewa Beach,

HI 96706.

Communities in Oregon can

request maps from the Oregon

Department of Geology and

Mineral Industries (DOGAMI)

by calling 503.731.4100 or by

writing 800 NE Oregon Street,

#28, Portland, OR 97232.

Washington and California

communities should contact

their state geologist for

mapping information.

What are the Characteristics of Tsunamis?

Debris: As the tsunami wave comes ashore, it brings with it debris from the

ocean, including man-made debris like boats, and as it strikes the shore,

creates more on-shore debris. Debris can damage or destroy structures on

land.

Distance from shore: Tsunamis can be both local and distant. Local tsunamis give

residents only a few minutes to seek safety and cause more devastation. Distant tsunamis originating in places like Chile, Japan, Russia, or Alaska can also cause damage.

High tide: If a tsunami occurs during high tide, the water height will be greater and cause

greater inland inundation, especially along flood control and other channels.

Outflow: Outflow following inundation creates strong currents, which rip at structures

and pound them with debris, and erode beaches and coastal structures.

Water displacement: When a large mass of earth on the ocean bottom impulsively

sinks or uplifts, the column of water directly above it is displaced, forming the tsunami

wave. The rate of displacement, motion of the ocean floor at the earthquake epicenter,

the amount of displacement of the rupture zone, and the depth of water above the rupture zone all contribute to the intensity of the tsunami.

Wave runup: Runup is the height that the wave extends up to on steep shorelines,

measured above a reference level (the normal height of the sea, corrected to the state of

the tide at the time of wave arrival).

Wave strength: Even small wave heights can cause strong, deadly surges. Waist-high

surges can cause strong currents that float cars, small structures, and other debris.

Tsunamis
Version 1.0 August 2001 2-19

profile hazard events 2

Tsunamis

Most tsunami mapping has been done at a statewide level.

If no local-level mapping has been done, you may consider hiring a

consultant to help develop or provide the following information:

Historic tsunami sources;

Potential future local and distant sources;

Potential for ground failures and other geologic effects that could

cause tsunamis;

An estimate of the number of waves, their heights, arrival times,

and inundation depths and distances;

Calculations of water velocities and debris loads; and

Estimates of the probabilities of occurrence and levels of certainty.

If you cannot find the necesary information to produce a tsunami profile, research past tsunami events in

your area and contact your state coastal zone manager for help identifying areas that would be susceptible to tsunami inundation. Indicate any

areas threatened by tsunami waves on your base map.

In addition, information is available from the following Websites:

 U.S. Geological Survey:

www.usgs.gov/themes/

coast.html

 University of Washington:

www.geophys.washington.

edu

 Pacific Marine Environmental Laboratory:

www.pmel.noaa.gov

Task C. Record your hazard

event profile information.

Transfer the boundary of your tsunami

hazard area onto your base map.

____

Go to the next

hazard on your list to

profile

or if you are finished with all your

hazard profiles,

Go to Step 3

____

Conditions that may exacerbate or mitigate the

effects of tsunamis

The following factors will affect the severity of a tsunami:

Coastline configuration: Tsunamis impact long, low-lying stretches

of linear coastlines, usually extending inland for relatively short distances.

Concave shorelines, bays, sounds, inlets, rivers, streams, offshore canyons, and flood control channels may create effects that result in greater

damage. Offshore canyons can focus tsunami wave energy, and islands

can filter the energy. The orientation of the coastline determines whether the

waves strike head-on or are refracted from other parts of the coastline. Tsunami waves entering flood control channels could reach a mile or more inland, especially if it enters at high tide.

Coral reefs: Reefs surrounding islands in the western North Pacific and the

South Pacific generally cause waves to break, providing some protection to

the islands.

Earthquake characteristics: Several characteristics of the earthquake that

generates the tsunami contribute to the intensity of the tsunami, including the

area and shape of the rupture zone, and:

Fault movement: Strike-slip movements that occur under the ocean create little or no tsunami hazard. However, vertical movements along a fault

on the seafloor displace water and create a tsunami hazard.

Magnitude and depth: Earthquakes with greater magnitude cause more

intense tsunamis. Shallow-focus earthquakes also have greater capacity to cause tsunamis.

Human activity: With increased development, property damage increases,

multiplying the amount of debris available to damage or destroy other

structures.
2-20 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task B. Obtain tornado hazard event profile

information.

Find your design wind speed.

Find your planning area on the "Design Wind Speed" map from

FEMA's Taking Shelter from the Storm: Building a Saferoom in Your

House publication 320. This map is based on design wind speeds set

forth by the American Society of Civil Engineers (ASCE).

(This publication can be viewed at http://www.fema.gov/fima/

tsfs02.shtm or ordered from the FEMA Publication Center.) Look up

the wind zone and indicated speed for your planning area. For

example if you live in Fayetteville, North Carolina, you would find

that you are located in wind zone III, which is associated with

200-mph wind speeds.

Unlike some other hazards, mapping the tornado risk is less important because it is unlikely that a community has variable tornado

risks within its jurisdiction. In most cases, communities need only

determine that they have a tornado risk (from Step 1) and then

proceed to determine their design wind speed. (See “Tip” on page

2-21.)

What is a Tornado?

A tornado is a violently rotating column of air extending

from a thunderstorm to the

ground. The most violent tornadoes are

capable of tremendous destruction with

wind speeds of 250 mph or more. Damage paths can be in excess of 1 mile wide

and 50 miles long.

Tornadoes are among the most unpredictable of weather phenomena. While

tornadoes can occur almost anywhere

in the world, they are most prevalent in

the United States. According to the National Weather Service, about 42 people

are killed because of tornadoes each

year. Tornadoes can occur in any state

but are more frequent in the Midwest,

Southeast, and Southwest.

Tornado season runs ordinarily from

March through August; however, tornadoes can strike at any time of the year if

the essential conditions are present.

What Causes a Tornado?

Thunderstorms and hurricanes spawn

tornadoes when cold air overrides a layer

of warm air, causing the warm air to rise

rapidly. The winds produced from hurricanes, earthquake-induced fires, and

wildfires have also been known to produce tornadoes.

The frequency of tornadoes in the nation's

midsection is the result of the recurrent

collision of moist, warm air moving north

from the Gulf of Mexico with colder fronts

moving east from the Rocky Mountains.

States may have more

than one wind speed designation. You can either represent all of the wind speeds on

your base map or decide to

use the higher wind speed for

the whole state.

* Design Wind Speed measuring criteria 

 are consistent with ASCE 7-98

 – 3-second gust

 – 33 feet above grade

 – Exposure C

Source: ASCE 7-98

Tornadoes
Version 1.0 August 2001 2-21

profile hazard events 2

Task C. Record your hazard

event profile information.

1. If you are located in only one

Design Wind Speed zone, note that

zone on Worksheet #2 and go to the

bottom of this page, otherwise, continue with this task.

2. If you are located in more than one

Design Wind Speed zone, you will need

a copy of the Design Wind Speed

maps.

3. Transfer the boundary of your

Design Wind Speed zones on to your

base map.

4. Record the Design Wind Speed

zones on your base map.

____

Go to the next

hazard on your list to

profile

or if you are finished with all your

hazard profiles

Go to Step 3

____

The nature of tornadoes is that they strike at ran- dom. While it is known that some areas of the country experience

tornadoes more than others, predicting exactly what parts of your community or state have a greater chance of being struck by a tornado is

difficult.The NOAA Website http://www.outlook.noaa.gov/tornadoes has

tornado statistics broken out by state. It also identifies tornado events per 1,000

square miles.

In order to determine the likelihood and potential severity of tornado events in your

state or community, you should ascertain the number of tornadoes that have affected the area in the past and their intensity. Take note, however, that the past

number and severity of events is not necessarily a predictor of future occurrences.

To determine the magnitude of tornadoes that have affected your community or

state in the past, go to www.tornadoproject.com, click on "All Tornadoes" in the

navigation frame, and then click the link, “Every state in the USA.” The site provides

by state and county a list of all tornado occurrences and magnitudes for the years

1950 to 1995. Find your county and collect the recorded tornado history.

Tornadoes are categorized by damage pattern, F0 through F5. The table below

shows the tornado category, expected damages, and corresponding wind speed.

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The accuracy of expected damage at particular wind speeds has never been scientifically

proven.
2-22 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task B. Obtain coastal storm

hazard event profile

information.

The state hurricane program manager, who usually works for the state

emergency management office, will

have information on hurricanes,

Nor'easters, storm surge, and coastal

erosion and can provide a history of

storms that have affected the state.

Another source of information or

assistance is the state coastal zone

manager who should have information on state coastal hazards including information on habitat and

environmental resources that may

be affected by such hazards.

Inland communities will be most

concerned with the flooding aspect

of coastal storms. Torrential rains of

even Category One hurricanes and

tropical storms have been known to

cause 500-year floods (which have a

0.2% chance of occurring each

year) and greater flooding in inland

communities. Coastal communities

will need to determine how severe

the high winds, storm surge and

erosion could be from their storm

surge inundation map.

1. Get a copy of your FIRM.

Coastal flooding is shown on the

FIRM. Copies of FIRMs can be

requested by calling the FEMA Map

Service Center at 1.800.358.9616, on

the Internet at http://www.fema.

gov/maps, or by contacting a FEMA

Regional Office. Additionally, the

National Flood Insurance Program

What is a Coastal Storm?

Coastal storms can cause increases in tidal elevations (called storm

surge), wind speed, and erosion, caused by both extratropical events

and tropical cyclones.

Extratropical events include Nor'easters and severe winter low-pressure systems. Both West and East coasts can experience these non-tropical storms that

produce gale-force winds and precipitation in the form of heavy rain or snow. These

cyclonic storms, commonly called Nor'easters on the East Coast because of the

direction of the storm winds, can last for several days and can be very large –

1,000-mile wide storms are not uncommon.

A "tropical cyclone" is a generic term for a cyclonic, low-pressure system over

tropical or sub-tropical waters. Tropical cyclones with maximum sustained winds

of less than 39 mph are called tropical depressions. A tropical storm is a cyclone with maximum sustained winds greater than 39 mph and less than 74 mph,

and hurricanes are intense tropical weather systems with maximum sustained

winds of 74 mph or higher that develop over the north Atlantic Ocean, northeast

Pacific Ocean, or the south Pacific Ocean east of 160E longitude. A special category of tropical cyclone is a typhoon, which is peculiar to the western North

Pacific Basin, frequently affecting areas in the vicinity of Guam and the North

Mariana Islands. Typhoons whose maximum sustained winds attain or exceed

150 miles per hour are called super typhoons.

The primary focus of this section is on the effects of hurricanes although all these

types of coastal storms can have similar impacts in terms of wind damage, flooding and coastal erosion.

What is a Hurricane?

A hurricane is a category of tropical cyclone characterized by thunderstorms and

defined surface wind circulation. Hurricanes develop over warm waters and are

caused by the atmospheric instability created by the collision of warm air with

cooler air.

Hurricane winds blow in a large spiral around a calm center called the eye, which

can be 20-30 miles wide. When a hurricane nears land, it may bring torrential

rains, high winds, storm surges, coastal flooding, inland flooding, and, sometimes,

tornadoes. A single hurricane can last for more than two weeks over water and

can extend outward 400 miles. The hurricane season for the Atlantic Coast and

Gulf of Mexico is June 1 to November 30. On average, five hurricanes strike the

United States every year. In a two-year period, an average of three significant

(category 3 or higher; see Saffir-Simpson scale on page 2-23) hurricanes will

strike the United States. Duration depends on the forward motion of the storm and

the availability of a warm water source for energy.

Some hurricanes are characterized primarily by water – a rainy or wet hurricane –

while others are primarily characterized by wind – a windy or dry hurricane. Wet

hurricanes can flood both coastal and inland areas, even as the storm dissipates

in wind strength, while windy hurricanes primarily affect coastal areas with their

high winds and storm surge. You should, therefore, determine the location and the

expected severity of flooding, storm surge, and winds from hurricanes and tropical storms that may affect the community or state by finding expected areas of

flooding and peak gusts.

Because hurricanes are large, moving storm systems, they can affect entire states

or entire coastlines. Not only will coastal development be affected, but also areas

far inland can suffer direct impacts from hurricanes and tropical storms.

Coastal Storms
Version 1.0 August 2001 2-23

profile hazard events 2

(NFIP) Guide to Flood Maps is available on the web at http://msc.

fema.gov/MSC/hardcopy.htm and Flood Insurance Rate Map

(FIRM) information is available at http://www.fema.gov/fmapinfo.

htm. For more information on FIRMs, see page 2-10 to 2-14.

To request copies of your FIRM or to help you identify areas that

are prone to coastal hazards and storm surge, contact your NFIP

coordinator or floodplain manager. They usually work in the planning, building, engineering, or natural resources department.

Coastal communities or states with a coastline should determine

areas of coastal flooding, characterized as V zones and A zones,

oriented approximately parallel to the shoreline.

Coastal A zones are not currently

mapped or regulated by FEMA any differently than inland A zones; however,

flood hazards in coastal A zones, like

those in V zones, can include

the effects of waves, velocity

flow, and erosion (although

the magnitude of these effects

will be less than those in V

zones.)

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(continued on page 2-25)
2-24 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

How are

Pacific

Coast States

Different

than Atlantic and

Gulf Coast States?

Eastern and Central Pacific

hurricanes sometimes affect

the West Coast of North

America and the Hawaiian Islands. Easterly winds push

tropical cyclones that form off

the Mexican and Central American coasts out toward the Central Pacific. In the Eastern

Pacific, hurricanes or tropical

storms are more likely to bring

heavy rains, flash floods,

mudslides, and high winds to

Mexico's Pacific Coast than

the U.S southern California

coast.

Although the California coast

has not been hit by a hurricane-strength storm, it has

experienced heavy rain from

tropical storms and depressions in the past. While many

hurricanes form off the west

coast of Mexico, they tend to

move seaward. Rarely, when

a tropical cyclone reaches the

extreme southern California

coast, they tend to be weak

compared to East Coast hurricanes. Remnant moisture from

dissipated hurricanes or tropical storms sometimes brings

monsoon-like rains to the

Southwest.

Under tropical cyclone conditions, the Pacific Coast experiences storm surges of limited

magnitude because of the

great ocean depths close to

shore.

What are the Characteristics of Coastal Storms?

Storm surge: The most dangerous and damaging feature of a coastal storm is

storm surge. Storm surges are large waves of ocean water that sweep across

coastlines where a storm makes landfall. The more intense the storm, the greater

the height of the water. The higher the storm surge, the greater the damage to the coastline.

Storm surges inundate coastal areas, wash out dunes, cause backwater flooding in rivers,

and can flood streets and buildings in coastal communities. Storm surge areas can be mapped

by the probability of storm surge occurrences using Sea, Lake, and Overland Surges from

Hurricanes modeling (SLOSH) (see page 2-26).

Storm tide: If a storm surge occurs at the same time as high tide, the water height will be

even greater. Storm tide is the combination of the storm surge and the normal tide. For example, a 15-foot storm surge along with the normal 2-foot high tide creates a storm tide of 17

feet.

Inland Flooding: In recent years, most deaths related to hurricane and tropical storm activity have been the result of inland flooding. As hurricanes move across land bringing torrential

rains and backwater flooding from the ocean, rivers and streams overflow. Hurricanes and

tropical storms have been known to cause floods whose elevations represent greater than a

500-year probability of occurring in inland areas.

Water force: During hurricanes and other coastal storms, coastal areas will experience

flooding with velocity or "wave action," defined as areas subject to receiving waves on top of

the rising water from coastal flooding. The velocity and the force of the water make flooding

even more destructive. The velocity and wave action knock over buildings, move debris,

erode dunes, scour the shoreline, and displace and redeposit sand. Areas subject to coastal

flooding with velocity are designated as V or VE zones on FIRMs.

Wind velocity: The higher the wind speed, the greater the damage. Hurricane force winds

can travel hundreds of miles inland, creating substantial damage to buildings, vegetation, and

infrastructure.

Coastal erosion: Coastal erosion is the wearing away of coastal land. It is commonly used

to describe the horizontal retreat of the shoreline along the ocean, or the vertical downcutting

along the shores of the Great Lakes. Erosion is considered a function of larger processes of

shoreline change, which includes erosion and accretion. Erosion results when more sediment is lost along a particular shoreline than is redeposited by the water body. Accretion

results when more sediment is deposited along a particular shoreline than is lost. When these

two processes are balanced, the shoreline is said to be stable.

In assessing the erosion hazard in your community or state, it is important to realize that

there is a temporal, or time aspect associated with the average rate at which a shoreline is

either eroding or accreting. Over a long-term period (years), a shoreline is considered either

eroding, accreting or stable. When you evaluate coastal erosion in your community or state,

you should focus on the long-term erosion situation. However, in the short-term, it is important to understand that storms can erode a shoreline that is, over the long-term, classified as

accreting, and vice versa.

Erosion is measured as a rate, with respect to either a linear retreat (i.e., feet of shoreline

recession per year) or volumetric loss (i.e., cubic yards of eroded sediment per linear foot of

shoreline frontage per year). Erosion rates are not uniform, and vary over time at any single

location. Annual variations are the result of seasonal changes in wave action and water

levels.

Erosion is caused by coastal storms and flood events; changes in the geometry of tidal inlets,

river outlets, and bay entrances; man-made structures and human activities such as shore

protection structures and dredging; long-term erosion; and local scour around buildings and

other structures.

Further information on coastal erosion can be found in FEMA-55, Coastal Construction Manual,

FEMA's Multihazard Identification and Risk Assessment, Evaluation of Erosion Hazards

published by The Heinz Center, and Coastal Erosion Mapping and Management, a special

edition of the Journal of Coastal Research.
Version 1.0 August 2001 2-25

profile hazard events 2

2. Verify that the FIRM is up-to-date and complete.

If there has been a coastal

storm since the date of the

FIRM, the coastline and

hazard zones may no longer

be accurate. Coastal storms can

either erode or extend the

coastline, possibly causing the

flood hazard zones to change.

Consult your local floodplain

manager for further advice.

3. Determine the annual rate of

coastal erosion in your coastal

area.

Contact your State Coastal

Zone Management Program to

determine the annual longterm erosion rate in your area

of the state. This program may

be housed in a separate coastal

agency, an environmental

agency, or a water resources

agency. Once you know the

annual rate, multiply this rate

by the number of years over

which you are planning. Most

erosion maps consider a 30- or

60-year time frame. You would

then measure the amount of

erosion that would take place

over the 30- or 60-year timeframe from the existing shoreline and mark this on your

basemap.

4. Find your design wind speed.

Contact your state or local building code official to determine your

design wind speed.

Task C. Record your hazard event profile information.

1. Transfer the boundaries of your hurricane hazard areas (flooding

erosion) onto your base map.

2. Record the base flood elevations and wind zones on your base map.

States should be prepared

to assess the severity of a

hurricane statewide. Considerations like sheltering and

evacuation can be especially

problematic because, although these

may occur only along the coast, the repercussions of relocating thousands of

people inland may be felt across the

state.

(continued from page 2-23)

When coastal erosion occurs, shoreline geometry changes,

possibly causing flood hazard zones to change.
2-26 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

For more in-depth analysis of the hurricane probability and

effects in your area, you should contact your state coastal zone manager and/or your SHMO.Go to http://www.nhc.noaa.gov/aboutmeow.html

to find information on the inland wind model, which estimates the maximum sustained surface wind as a storm moves inland. This model can

be used to estimate the maximum inland strength of hurricane force winds (or any

wind threshold) for a given initial storm intensity and forward storm motion. You can

find examples of the Maximum Envelope of Winds (MEOW) based on the strength

and forward motion of hurricanes in three tables shown on the Web page, one for

each of the regions: Gulf Coast, East Coast, and Northeast Coast.

The National Hurricane Center (NHC), the U.S. Army Corps of Engineers (USACE),

the National Oceanographic and Atmospheric Administration (NOAA), the Federal

Emergency Management Agency (FEMA), and your state emergency management agency have detailed information about the hurricane risk in your community.

These organizations are important when doing detailed analysis of hurricane probabilities through SLOSH modeling and Hurricane Evacuation Studies. SLOSH is a

computerized model run by the NHC to estimate storm surge heights and winds

resulting from historical, hypothetical, or predicted hurricanes by taking into account pressure, size, forward speed, track, and winds.

The SLOSH boundaries may differ from the base flood boundary on the FIRM. The

SLOSH flood areas are determined by compositing the model surge values from

200-300 hypothetical hurricanes. The point of a hurricane's landfall is crucial to

determining which areas will be inundated by the storm surge. Where the hurricane

forecast track is inaccurate, SLOSH model results will be inaccurate. As a result,

the SLOSH model is best used for defining the potential maximum surge for a

location.

To determine whether a hurricane or tropical storm may affect your community or

state, you should find historical evidence of hurricane or tropical storm activity. At

http://www.nhc.noaa.gov/pastall.html you will find historical data and maps to locate past hurricane tracks that may have passed through or near your community

or state. The maps show all Atlantic tropical cyclone tracks and their wind strength

from 1927 to the present.

____

Go to the next

hazard on your list to

profile

or if you are finished with all your

hazard profiles

Go to Step 3

____

Conditions that may exacerbate or mitigate the

effects of coastal storms

The following factors will affect the severity of a coastal storm:

Coastal shape: Concave shoreline sections sustain more damage

because the water is driven into a confined area by the advancing storm,

thus increasing storm surge height and storm surge flooding.

Storm center velocity: The slower the storm moves, the greater the damage. The worst possible situation is a storm that stalls along a coast, through

several high tides.

Nature of coast: Rocky coasts are least disturbed. Cliffs along coasts with

sedimentary deposits can retreat by slumping or rock falls, but damage is

most severe on low-lying barrier island shorelines because they are easily

overwashed by storm waves and storm surge.

Previous storm damage: A coast weakened by even a previous minor

storm may be subject to proportionally greater damage in a subsequent storm.

Human activity: With increased development, property damage increases,

multiplying the amount of floating debris available to damage or destroy other

structures.

Hardened sand and flood control structures: Structures such as groins,

jetties, or seawalls exacerbate localized scour and erosion and can be undermined, resulting in collapse (particularly seawalls).
Version 1.0 August 2001 2-27

profile hazard events 2

Task B. Obtain landslide hazard event profile

information.

The best predictor of future landslides is past landslides because

they tend to occur in the same places. Landslides, like other geologic hazards, are very complex and require someone with geologic

expertise to conduct a geotechnical study. You should start by

talking to your local or state geology, planning, public works or

engineering departments, which should have information on past

landslides. These agencies can provide maps, as well as information

about causes, damage, deaths, injuries, and areas impacted by past

landslides. If current maps are not available, the specialists mentioned above can help create one for your community.

It is important to consult with a local geologist or other professional

familiar with past landslides in order to interpret landslide hazard

information.

1. Identify high-hazard areas on your map.

Identify existing or old landslides:

 On or at the base of slopes;

 In or at the base of minor drainage hollows;

 At the base or top of an old fill slope;

 At the base or top of a steep cut slope; or

 Developed hillsides where leach field septic systems are

used.

2. Map the topography.

Topographic maps can be obtained from the USGS or your state

geologic survey. Specifically, you will need to know where the steep

slopes are. Steeper slopes have a greater probability of landslides.

Contact your state geological survey or natural resources department for more information or help in interpreting topographic

maps.

3. Map the geology.

Underlying geology also plays an important part in the review of

slope. In addition to slope angle, the presence of rock or soil that

weakens when saturated, as well as poorly drained rock or soil are

indicators of slope instability as well. Contact a local geologist or

state geological survey for more information or assistance in identifying the various geological features of your community or state.

What is a

Landslide?

Landslides are described as

downward movement of a

slope and materials under the force of

gravity. The term landslide includes a

wide range of ground movement, such

as rock falls, deep failure of slopes, and

shallow debris flows. Landslides are influenced by human activity (mining and

construction of buildings, railroads, and

highways) and natural factors (geology,

precipitation, and topography). They are

common all over the United States and

its territories.

What Causes a Landslide?

Landslides occur when masses of rock,

earth, or debris move down a slope.

Therefore, gravity acting on an overly

steep slope is the primary cause of a

landslide. They are activated by storms,

fires, and by human modifications to the

land. New landslides occur as a result of

rainstorms, earthquakes, volcanic eruptions, and various human activities.

Measures of Landslides

Mudflows (or debris flows) are flows of

rock, earth, and other debris saturated

with water. They develop when water rapidly accumulates in the ground, such as

during heavy rainfall or rapid snowmelt,

changing the earth into a flowing river of

mud or "slurry."

Slurry can flow rapidly down slopes or

through channels and can strike with little

or no warning at avalanche speeds.

Slurry can travel several miles from its

source, growing in size as it picks up

trees, cars, and other materials along the

way.

Other types of landslides include: rock

slides, slumps, mudslides, and earthflows. All of these differ in terms of content and flow.

Landslides
2-28 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

The three most useful typesof landslide

maps are (1) landslide inventories, (2) landslide susceptibility maps, and (3)

landslide hazard maps.

Landslide inventories identify areas that

appear to have failed due to landslides,

including debris flows and cut-and-fill failures. Detailed inventories depict and classify each landslide and show scarps,

zones of depletion and accumulation,

active versus inactive slides, geological

age, rate of movement, and other pertinent data on the depth and type of materials involved in sliding. Overlaying a

geologic map with an inventory map that

shows existing landslides can identify

specific landslide-prone geologic units.

For this reason, a landslide inventory is

essential for preparing a landslide susceptibility map.

Landslide susceptibility maps depict

areas that have the potential for landslides

by correlating some of the principal factors that contribute to landslides – steep

slopes, geologic units that lose strength

when saturated, and poorly drained rock

or soil – with the past distribution of landslides. These maps indicate the relative

stability of slopes; however, they do not

make absolute predictions. More complex maps may include additional information such as slope angle, and

drainage.

Landslide hazard maps show the real

extent of the threat: where landslides have

occurred in the past, where they are likely

to occur now, and where they could occur in the future. They contain detailed

information on the types of landslides,

extent of slope subject to failure, and probable maximum extent of ground movement. These maps can be used to predict

the relative degree of hazard in a landslide area.

Task C. Record your hazard event profile information.

Mark the areas susceptible to landslides on your base map.

____

Go to the next hazard on your list to

profile

or if you are finished with all your hazard profiles

Go to Step 3

____

Conditions that may exacerbate or mitigate the

effects of landslides

The following factors will affect the severity of a landslide:

Erosion – Erosion caused by rivers, glaciers, or ocean waves created by overly steep slopes.

Unstable slopes – Rock and soil slopes are weakened through saturation

by snowmelt or heavy rains.

Earthquakes – The shaking from earthquakes creates stress that makes

weak slopes fail.

Volcanic eruptions – Eruptions produce loose ash deposits and debris

flows.

Vibrations – Machinery, traffic, blasting, and even thunder may cause vibrations that trigger failure of weak slopes.

Increase of load – Weight of rain/snow, fills, vegetation, stockpiling of rock

or ore from waste piles, or from man-made structures may cause weak

slopes to fail.

Hydrologic factors – Rain, high water tables, little or no ground cover,

numerous freeze/thaw cycles may cause weak slopes to fail.

Human activity – These include development activities such as cutting

and filling along roads and removal of forest vegetation. Such activities are

capable of greatly altering slope form and ground water conditions which

can cause weak slopes to fail.

Removal of lateral and underlying support – Erosion, previous slides,

road cuts and quarries can trigger failure of weak slopes.

Increase of lateral pressures – Hydraulic pressures, tree roots, crystallization, swelling of clay soil may cause weak slopes to fail.

Regional tilting – Geological movements can trigger weak slopes to fail.
Version 1.0 August 2001 2-29

profile hazard events 2

Task B. Obtain wildfire hazard event profile

information.

Wildfire hazard maps won't show the extent or range of where a

wildfire will occur because they are dependent on the amount of

fuel available, weather conditions, and wind speed and direction.

On the other hand, wildfire hazard maps should show geographic

locations of where wildfires have taken place in the past and areas

that are prone to wildfires.

Contact your state forest service at http://www.stateforesters.org/

sflist.html or your USFS Region office at http://www.fs.fed.us/

intro/directory/orgdir.htm for wildfire mapping information.

1. Map the fuel models located within the urban-wildland interface area of

your community.

Use the fuel model key (page 2-31)excerpted from the National Fire

Danger Rating (NFDR) System, 1978, U.S. Department of Agriculture (USDA) Forest Service, as a guide, to determine the fuel model

classifications within your community or state. It represents all

wildfire fuels from Florida to Alaska and from the East Coast to

California, so they are only general descriptions.

You can also download the USDA fuel model map from the Internet

at: http://www.fs.fed.us/land/wfas/nfdr_map.htm. The USDA map

was designed to assess fire danger across the continental United

States and may not be site specific.

Using the fuel model key, map the various fuel classifications based

on the following categories:

 Heavy Fuel is vegetation consisting of round wood 3 to 8

inches in diameter. (fuel models G, I, J, K and U on the

fuel model key)

 Medium Fuel is vegetation consisting of round wood 1/3

to 3 inches in diameter. (fuel models B, D, F, H, O, Q,

and T on the fuel model key)

 Light Fuel is vegetation consisting of herbaceous plants

and round wood less than 1⁄4 inch in diameter. (fuel

models A, C, E, L, N, P, R and S on the fuel model key)

For more information or assistance contact your local arborist or

state forestry or natural resources department.

Wildfires

What is a Wildfire?

A wildfire is an uncontrolled fire

spreading through vegetative

fuels, exposing and possibly

consuming structures. They often begin

unnoticed and spread quickly and are usually signaled by dense smoke that fills the

area for miles around. Naturally occurring

and non-native species of grasses, brush,

and trees fuel wildfires.

A wildland fire is a wildfire in an area in

which development is essentially nonexistent, except for roads, railroads, power

lines and similar facilities. An Urban-Wildland Interface fire is a wildfire in a geographical area where structures and other

human development meet or intermingle

with wildland or vegetative fuels.

States with a large amount of wooded,

brush and grassy areas, such as California, Colorado, New Mexico, Montana, Kansas, Mississippi, Louisiana, Georgia,

Florida, the Carolinas, Tennessee, Massachusetts, and the national forests of the

western United States are at highest risk

of wildfires. Additionally, areas anywhere

that have experienced prolonged droughts,

or are excessively dry, are also at risk of

wildfires.

People start more than four out of every

five wildfires, usually as debris burns, arson, or carelessness. Lightning strikes are

the next leading cause of wildfires.

Wildfire behavior is based on three primary

factors:

Fuel

Topography

Weather

The type, and amount of fuel, as well as its

burning qualities and level of moisture affect wildfire potential and behavior. The continuity of fuels, expressed in both

horizontal and vertical components is also

a factor, in that it expresses the pattern of

vegetative growth and open areas.

Topography is important because it affects

the movement of air (and thus the fire) over

the ground surface. The slope and shape

of terrain can change the rate of speed at

which the fire travels.

Weather affects the probability of wildfire

and has a significant effect on its behavior.

Temperature, humidity and wind (both

short and long term) affect the severity and

duration of wildfires.
2-30 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

2. Map the topography.

In general terms, the steeper the slope of the land, the faster a fire

can spread up the slope. Using a topographic map, identify areas of

your community or state with slopes less than 40%, between 41%

and 60%, and greater than 61%, corresponding to low, moderate

and steep gradients relative to the spread of wildfires.

Contact your state geological survey or natural resources department for more information or help with topographic maps.

3. Determine your critical fire weather frequency.

This is a set of weather conditions, usually a combination of low

relative humidity and wind, whose effects on fire behavior make

control difficult and threaten firefighter safety. The average number of days per year of critical fire weather experienced in your

community or state can be obtained from your local or state fire

marshal, forestry department, or department of natural resources.

The National Weather Service or NOAA Websites can help you

determine past weather conditions.

4. Determine your fire hazard severity.

Using the Fire Hazard Severity Table below, determine your fire

hazard severity. You may have more than one classification in your

community or state depending on the degrees of the slope and fuel

models. For example, if you experience an average of five critical

fire weather days per year, have heavy fuel, and less than 40° slopes,

then you are in a high fire hazard area. If your average number of

days of critical fire weather per year increases above eight, you

would be in an extreme fire hazard area.

Task C. Record your hazard event profile information.

Draw the boundaries of your wildfire hazard areas onto your base map.

Most communities

or regions should have one

critical fire weather frequency

number; however, states may

have more than one zone depending on climatic and atmospheric conditions. The state forester should be

prepared to assist communities in determining their critical fire weather frequency, as well as the type of fuel

models to use, and the fuel loading

levels.

Visitthe USFS Website at http://www.fs.fed.us

/links/maps.shtml/ or the

USGS Website at http://

mcmcweb. er.usgs.gov/

topomaps/ for general information about

topographic maps, finding and ordering

topographic maps, and an explanation of

topographic map symbols.

ytireveSdrazaHeriF

ycneuqerFrehtaeWeriFlacitirC

raeY/yaD1< raeY/syaD7ot2 raeY/syaD8>

)%(epolS )%(epolS )%(epolS

leuF

noitacifissalC 04< 06-14 16> 04< 06-14 16> 04< 06-14 16>

L MMMMMMMMH leuFthgi

M MMHHHHE E E leuFmuide

H HHHH leuFyvae EEEEE

Source: Urban Wildland Interface Code: 2000

M d drazahetaredoM= H d razahhgiH= razahemertxE=E

If you cannot find the

necessary information to produce a wildfire profile contact

your fire marshall or state forest service for help identifying fire prone areas of grasslands or

dense wooded areas. Research past or

historic wildfire events and use eyewitness accounts to delineate the approximate wildfire boundaries. Indicate these

areas on your base map as potential wildfire hazard areas.
Version 1.0 August 2001 2-31

profile hazard events 2

I. Mosses, lichens, and low shrubs predominate ground fuels.

A. An overstory of conifers occupies more than one-third of the site: MODEL Q.

B. There is no overstory, or it occupies less than one-third of the site (tundra): MODEL S.

II. Marsh grasses and/or reeds predominate: MODEL N.

III. Grasses and/or forbs predominate.

A. There is an open overstory of conifer and/or hardwood trees: MODEL C.

B. There is no overstory.

1. Woody shrubs occupy more than one-third, but less than two-thirds of the site; MODEL T.

2. Woody shrubs occupy less than one-third of the site.

a. The grasses and forbs are primarily annuals; MODEL A.

b. The grasses and forbs are primarily perennials: MODEL L.

IV. Brush, shrubs, tree reproduction or dwarf tree species predominate.

A. Average height of woody plants is 6 feet or greater.

1. Woody plants occupy two-thirds or more of the site.

a. One-fourth or more of the woody foliage is dead.

(1) Mixed California chaparral: MODEL B.

(2) Other types of brush: MODEL F.

b. Up to one-fourth of the woody foliage is dead; MODEL Q.

c. Little dead foliage: MODEL O.

2. Woody plants occupy less than two-thirds of the site: MODEL F.

B. Average height of woody plants is less than 6 feet.

1. Woody plants occupy two-thirds or more of the site.

a. Western United States; MODEL F.

b. Eastern United States: MODEL O.

2. Woody plants occupy less than two-thirds but more than one-third of the site.

a. Western United States; MODEL T.

b. Eastern United States; MODEL D.

3. Woody plants occupy less than one-third of the site.

a. The grasses and forbs are primarily annuals: MODEL A.

b. The grasses and forbs are primarily perennials: MODEL L.

V. Trees predominate.

A. Deciduous broadleaf species predominate.

1. The area has been thinned or partially cut, leaving slash as the major fuel component; MODEL K.

2. The area has not been thinned or partially cut.

a. The overstory is dormant; the leaves have fallen: MODEL E.

b. The overstory is in full leaf: MODEL R.

B. Conifer species predominate.

1. Lichens, mosses, and low shrubs dominate as understory fuels: MODEL Q.

2. Grasses and forbs are the primary ground fuels: MODEL C.

3. Woody shrubs and/or reproduction dominate as understory fuels.

a. The understory burns readily.

(1) Western United States: MODEL T.

(2) Eastern United States:

(a) The understory is more than 6 feet tall: MODEL O.

(b) The understory is less than 6 feet tall: MODEL D.

b. The understory seldom burns; MODEL H.

4. Duff and litter, branchwood, and tree boles are the primary ground fuels.

a. The overstory is overmature and decadent; there is a heavy accumulation of dead tree debris: MODEL G.

b. The overstory is not decadent; there is only nominal accumulation of debris.

(1) The needles are 2 inches or more in length (most pines).

(a) Eastern United States: MODEL P.

(b) Western United States: MODEL U.

(2) The needles are less than 2 inches long: MODEL H.

VI. Slash is the predominant fuel.

A. The foliage is still attached; there has been little settling.

1. The loading is 25 tons/acre or greater; MODEL I.

2. The loading is less than 25 tons/acre but more than 15 tons/acre: MODEL J.

3. The loading is less than 15 tons/acre: MODEL K.

B. Settling is evident; the foliage is falling off; grasses, forbs, and shrubs are invading the area.

1. The loading is 25 tons/acre or greater: MODEL J.

2. The loading is less than 25 tons/acre: MODEL K.

Fuel

Model Key

Source:

Urban Wildland

Interface Code: 2000
2-32 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

The Wildland Fire Assessment System (WFAS) was

created to help evaluate risk factors, which vary depending on current

and past weather conditions, fuel types and moisture. Observations are

reported daily during peak wildfire season, from late winter to early spring,

to the Weather Information Management System (WIMS). The information is processed by the National Fire Danger Rating System (NFDRS), which

creates national maps of selected fire weather and fire danger components.

Copies of the maps can be viewed on the WFAS Website (the address is located in

Appendix A).

The fire danger map described above indicates low to extreme fire danger values

for the United States based on past and current weather, fuel types, and the presence of live and dead fuel moisture.

In addition to the fire danger maps referenced above, communities and states should

map areas of past wildfire damages. This information is available from the local or

state emergency management agency or fire department. Areas with significant

fuel sources located adjacent to developed areas are prime risks for wildfire damage and should be mapped as well.

Even if your community is not especially close to a source of burning, you should

be aware that fires in nearby areas could quickly and easily spread into your community.

Conditions that may exacerbate or mitigate the effects of wildfires

The following factors will affect the severity of a wildfire:

Climatic Considerations – Areas of extreme climate conditions, including temperature, relative humidity, wind speed and duration of high velocity, precipitation, wind direction, fog and other atmospheric conditions.

Topographic Considerations – elevation and ranges of elevation, location

of ridges, drainages and escarpments, percent of grade (slope), location of

roads, bridges and railroads.

Geographic Considerations – Fuel types, concentration in a mosaic and

distribution of fuel types, earthquake fault zones, hazardous material routes.

Flammable material on structure exteriors.

Narrow roadways leading to developed areas.

Inadequate hydrants or poorly placed hydrants.

Combustible landscaping or debris near structures.

Development – increased development and human activity in and near the

wildland interface.
Version 1.0 August 2001 2-33

profile hazard events 2

____

Go to the next hazard on your list to

profile

or if you are finished with all your hazard profiles

Go to Step 3

____

Click to proceed to

Step 3

Return to

Table of Contents
step
3

Version 1.0 August 2001 3-1

inventory

assets

Overview

The third step in the risk assessment process answers the question: What assets in the community or state will be affected by

the hazard event?

Now that you know where natural hazard events can affect your

community or state, you will conduct an inventory of the vulnerable

assets. The inventory will help you understand what can be affected

by the different hazard events.

You will first develop and map a general inventory of assets in your

community or state. Then, using the maps developed previously in

Step 2, you will identify the assets inside your hazard areas. For

example, using your floodplain maps from Step 2, you will identify

all of the assets within the 100-year floodplain boundary. However,

some hazards can affect the entire community (such as earthquakes

or tornadoes) and some will only affect limited areas. Thus, the

unique combinations of hazards that can affect you will determine

how much inventory collection will be appropriate. An initial

inventory can be done very quickly and easily using the baseline

data contained in HAZUS.

Information regarding

the amount of population and

building stock located in the

hazard areas can provide a

powerful initial glimpse into the

nature of the community's vulnerability

to natural hazards. This can help secure

political and community support and funding for mitigation planning and for the

projects to be later identified.

HAZUS contains inventory information for every

community in the United

States. While HAZUS is currently used for generating

earthquake loss estimates, it can also

be used to inventory elements exposed

to other hazards. The package includes

GIS maps showing schools, street roadway maps at the county level, SLOSH

basin maps outlining areas that can be

inundated by hurricane surges, Q3 flood

data maps indicating floodplains at the

county level, and land use/land cover

maps, among others.

HAZUS also allows users to update and

add location-specific data. For more information on using HAZUS, see the

HAZUS Users Manual or contact your

FEMA regional office.

A GIS system will also allow your community to access and use the data available in HAZUS. For example, if you have

a GIS flood layer, you may be able to

estimate the number of people living in

or near flood hazards areas by census

tract or compute the current value of

property located in the flood hazard area.

In either case, two things are important:

Be consistent. In order to perform any

comparisons in subsequent steps and

phases of the mitigation planning, you

should strive to use a consistent method

for evaluating and recording information

about elements of your community. This

is especially important if more than one

person will be gathering information. You

want to avoid subjective opinions and

judgments from the process as much as

possible.

Keep good records. The information you

collect at this phase will be of value

throughout the remainder of the planning

process.

Your community’s assets may include

hospitals, schools, museums, apartment

buildings, and public infrastructure or utilities such as bridges or overhead power

lines.

(continued on page 3-4)
3-2 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task A. Determine the proportion of buildings, the value of buildings, and the population in your community

or state that are located in hazard areas.

Hazard _______________________________________

Worksheet #3a Inventory Assets step 

Date: July, 2001 What will be affected by the hazard event?

Task B. Determine whether (and where) you want to collect additional inventory data.

1. Do you know where your greatest damages may occur in your hazard areas?

2. Do you know whether your critical facilities will be operational after a hazard event?

3. Is there enough data to determine which assets are subject to the greatest potential

damages?

4. Is there enough data to determine whether significant elements of the community

are vulnerable to potential hazards?

5. Is there enough data to determine whether certain areas of historic, environmental,

political, or cultural significance are vulnerable to potential hazards?

6. Is there concern about a particular hazard because of its severity, repetitiveness,

or likelihood of occurrence?

7. Is additional data needed to justify the expenditure of community or state funds for

mitigation initiatives?

 Y N

_____ _____

_____ _____

_____ _____

_____ _____

_____ _____

_____ _____

_____ _____

Type of

Structure

(Occupancy

Class)

Number of Structures Value of Structures Number of People

# in

Community

or State

# in

Hazard

Area

% in

Hazard

Area

$ in

Community

or State

$ in

Hazard

Area

% in

Hazard

Area

# in

Community

or State

# in

Hazard

Area

% in

Hazard

Area

Residential

Commercial

Industrial

Agricultural

Religious/

Non-profit

Government

Education

Utilities

Total

Flood

61

5

0

2

3

7

1

2

81

16

4

0

1

1

5

1

2

30

25%

80%

0%

50%

33%

71%

100%

100%

37%

3,927,000

6,500,000

0

175,000

3,450,000

7,055,000

500,000

2,750,000

24,351,000

439,000

4,500,000

0

90,000

1,500,000

2,555,000

500,000

2,750,000

11,884,000

11%

69%

0

51%

43%

36%

100%

100%

49%

403

570

0

10

351

570

125

15

2,044

69

345

0

5

1

170

125

15

730

7%

61%

0

50%

0.2%

30%

100%

100%

44%













?

Joe, I think we need to do some

more research.
Version 1.0 August 2001 3-3

inventory assets 3

Task C. Compile a detailed inventory of what can be damaged by a hazard event.

Inventory the assets (critical facilities, businesses, historic, cultural, and natural resource areas, and areas of

special consideration), that can be damaged by a hazard event.

Hazard _______________________________________

Worksheet #3b Inventory Assets step 

Date: August, 2001 What will be affected by the hazard event?

Name or

Description of

Asset

Sources of

Information

Size of

Building

(sq ft)

Replacement

Value

($)

Contents

Value

($)

Function

Use or

Value

($)

Displacement

Cost

($ per day)

Occupancy

or Capacity

(#)

Other

Hazard

Specific

Information

     Critical Facility Vulnerable Populations Economic Assets Special Considerations Historic/Other Considerations

Historic

Lighthouse

Lighthouse

Preservation Society  3,000 $150,000 $1.5M $0.5M $500 1

Bridge Public

Works

250 ft long  $750,000 NA $31,750 $12,000 20

Sewage Treatment Plant Public Works  75,000 $2.5M $2.5M $30M $200,000 10

STP

Outbuilding

Public Works  10,000 $1M $1.5M $0.25M $5,000 —

STP

Outbuilding

Public Works  7,500 $75,000 $1.5M $0.5M $1,000 —

Water Treatment Plant Public Works  3,000 $250,000 $1.25M $1M $2,000 5

Hospital Hospital  45,000 $2.5M $3.75M $0.75M $2,500 100

Police/Fire

Station

Police Dept.  10,000 $2M $3M $0.35M $2,000 150

Flood
3-4 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

HAZUS can summarize the number and value of structures in your

jurisdiction by the types of structure or the occupancy class. For

example, if you wanted to know how many residential or commercial structures were in your community or state, you would select a

summary by the building occupancy class. If you wanted to know

how many manufactured homes or wood framed buildings were in

your community or state, you would select a summary by the building structure type.

After assessing the number and value of the buildings and the size

of the population within the hazard areas, you will decide if you

should end your inventory data collection or continue to gather

additional information to identify the extent to which the assets

would be damaged by the hazard events. If you decide to gather

additional information, you will then collect details on specific types

of population, building stock, infrastructure, and lifelines in the

hazard areas in the order of their importance to the community.

This information will be necessary to generate the loss estimations

you will make in Step 4.

You will use Worksheet #3: Inventory Assets in Appendix C (see

example on pages 3-2 and 3-3) to keep track of the inventory data

you will gather. Photocopy the worksheet for each hazard you are

assessing. If you have many assets to inventory, you may want to use

HAZUS databases or create a computerized spreadsheet to make

your data collection efforts more manageable.

Procedures & Techniques

Task A. Determine the proportion of buildings, the

value of buildings, and the population in your community or state that are located in hazard areas.

1. Estimate or count the total number of buildings, value of buildings, and

number of people in your community or state.

Using local resources, Census data, HAZUS, or other GIS capabilities, you will determine the total number and value of buildings and

the population within your jurisdiction.

a. Determine the total

number of buildings

inside your community

or state. Identify the

total number of buildings located within your

community or state.

States can use

worksheet #3 to compile the

inventory data from each of

the local community risk assessments.

U.S. Census Bureau

TIGER files are available from

http://www.census.gov/geo/

www/tiger.

To estimate the

total replacement

value of the buildings in

your community or state,

multiply the average building

replacement value by the number of

buildings. HAZUS can help you.

Remember that so far, you have

only been considering one hazard event

for each hazard type. Later in the process, you may find the need

to assess additional or possibly all potential hazard

events. This may expand or

decrease your planning area.

(continued from page 3-1)
inventory assets 3

Version 1.0 August 2001 3-5

This information can be grouped by occupancy class,

such as residential, commercial, or industrial in HAZUS

or can be gathered from a tax assessment map, aerial

photograph or local planning document.

b. Determine the total estimated value of the buildings

inside your community or state. Establish the total

approximate replacement value of the buildings located

inside the hazard area. This information is also estimated

by occupancy class in HAZUS or can be gathered from

the tax assessment values of individual buildings, or by

developing an estimate for the area as a whole.

c. Determine the number of people inside your community

or state. Estimate the current population inside your

jurisdiction. Use HAZUS, current Census data, or local

figures to estimate the current population. You should

note whether or not you have large daytime, nighttime,

or seasonal differences in your population.

2. Estimate the total number of buildings, total value of buildings, and

number of people in each of your hazard zones.

You will now use HAZUS, GIS, or printed maps to overlay the

hazard areas developed in Step 2 on top of your base map to determine the number and value of the buildings and the population

that is vulnerable to the hazard events.

a. Determine the total number of buildings inside the

hazard area. Establish the total number of buildings

located inside the hazard area for each hazard type. You

can use HAZUS to group the buildings by occupancy

class or use GIS, a tax assessment map, or aerial photograph to determine the number of buildings in the

hazard area.

b. Determine the total estimated value of the buildings

inside the hazard area. Establish the total approximate

replacement value of the buildings located inside the

hazard area. You can use HAZUS, GIS, tax assessment

values, or develop an estimate of the value of the buildings inside the hazard area as a whole.

c. Determine the number of people inside the hazard area.

Estimate the current population inside the hazard area.

Use HAZUS, current Census data, local figures, or an

estimate of the population. Once again, you should note

if there is a large daytime, nighttime, or seasonal population change inside the hazard area.

Estimating future

development will be addressed in the next phase of

the Mitigation Planning Process. The phase “Develop a

Mitigation Plan” will include how-to guidance on estimating future land use and

population and will account for future

risks. For now, you should note areas

where future development or redevelopment may occur, to determine whether

those areas are subject to hazards.

Your inventory should characterize a building and its contents, as well

as its functions and the effect of the function on the buildings, its service to the

community or state and its effect on the

economy. You should ask yourself, what

would happen to the community or state

if the building's function were

interrupted?

For example, providing drinking water is a normal function

of local government, usually

undertaken by the public

works department. If your water treatment plant is located in a hazard area

and can be damaged by a natural hazard event such as a flood or an earthquake, then it should be included in your

inventory. In addition to the potential for

physical damage to the plant itself, you

should estimate the cost to businesses

and residents for the period of time in

which potable water might not be available.
3-6 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

3. Calculate the proportion of assets located in hazard areas.

To determine the proportion of structures, building value, or people

in your hazard areas compared to your community or state, divide

the number or value in your hazard area by the

total number or value in your jurisdiction. For

example, if you determined that you have 20

residential structures in your community and 10 of

those are located in the 100-year floodplain, then

50 percent, or 10 divided by 20, of your residential

structures are located in your flood hazard area.

4. Determine the location of expected growth in your

community.

By referring to your local comprehensive plan, or

by talking with community officials, learn where

future growth is expected to take place. Note

whether these areas lie within hazard areas.

States should inventory (or arrange for

communities to perform these assessments as part

of their inventories) state facilities (including critical

facilities) and properties lying in hazard areas, including:

Infrastructure such as highways, bridges, waterways, and

utilities;

Air, water, and other transportation terminals or ports;

Lifelines and communication systems, such as phone lines

and antennae, or water and sewage treatment plants; and

Public recreation areas, parks, or forests.

As you complete your inventory, determine how you will incorporate the results into your statewide risk assessment.

You should begin to see the pattern of potential damage across

the state as communities complete their individual inventories.

A map showing the

location of the

community’s assets

can be produced...

...by overlaying the

base map for the

community...

...with a map

delineating hazard

area boundaries.

An overlay can be produced by hand using a light table or

through the use of GIS.

Using a light table (or

GIS if available), overlay this

information to see which

structures are located in more

than one hazard zone and

which areas of the community or state

are more or less susceptible to different

hazards.

This overlay mapping technique will

also be helpful in looking at

areas within the community

that are not currently developed but could be in the future. There is

no better time to avoid potential problems

than before ground is broken for residential, commercial, or industrial land uses.

By determining if any areas in the community that could be developed are prone

to specific hazards, actions can be taken

in advance that will serve to limit loss of

life and property in the event of a disaster event.
inventory assets 3

Version 1.0 August 2001 3-7

Task B. Determine whether (and where) you want to

collect additional inventory data.

This is a critical juncture in your risk assessment. You may decide to

end your inventory at this point, knowing the total estimated

population, number of buildings, and value of buildings in the

hazard areas, or you may decide to continue to gather additional

inventory information described in Task C.

Ending your inventory now will only provide you a very broad

picture of the potential extent of damage likely from a hazard

event. When time, money, or other resources are scarce, a truncated

inventory such as this can be helpful in demonstrating in a very

broad sense what your community stands to lose during a hazard

event. It can be particularly useful to convince decision-makers of

the need for further study to determine potential losses from

certain hazards. However, these figures will NOT allow you to

specify the structures that are at greatest risk of damage, making

objective determination of mitigation priorities difficult in the next

phase of the planning process.

Collecting additional information will allow you to determine to

what extent your assets can be damaged in a hazard event, giving

you a more accurate estimate of the losses (cost of damages) to your

community. At this time, loss estimation factors are available for

floods, coastal storms, and earthquakes. In order to benefit from the

use of these factors, you will need to gather additional inventory

information.

The decision whether to gather additional information for some or

all of your hazard areas is a subjective one. Your decision may be

based on your need for detailed hazard- or site-specific information

or the need to determine where to focus your information or the

need to determine where to focus your mitigation efforts as part of

the next phase of the Natural Hazard Mitigation Planning Process.

As you decide how much information to collect, ask yourself these

questions:

1. Is there enough data to determine which assets are

subject to the greatest potential damages?

2. Is there enough data to determine whether significant

elements of the community are vulnerable to potential

hazards?

3. Is there enough data to determine whether certain areas

of historic, environmental, political, or cultural significance are vulnerable to potential hazards?

Community

Vulnerability

Assessment Tool

(CVAT) CD-ROM

The CVAT can be used to run a preliminary vulnerability assessment to help

you determine whether or where you

would like to spend more time or resources on collecting additional data. The

CVAT provides guidance on conducting

community-wide vulnerability assessments. It also provides a case study demonstrating the process for analyzing

physical, social, economic, and environmental vulnerability to hazards at the local level. For more information, visit the

NOAA Web site at http://www.csc.

noaa.gov/products.
3-8 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

4. Is there concern about a particular hazard because of its

severity, repetitiveness, or likelihood of occurrence?

5. Is additional data needed to justify the expenditure of

community or state funds for mitigation initiatives?

You may want to gather detailed loss information on all of your

potential hazards, one hazard, or a particular area or neighborhood

affected by a hazard. You may also decide to gather detailed loss

information for all your critical and essential facilities, or you may

focus your attention on just the schools or hospitals. Additionally, if

you plan to use the loss information to help you identify and/or

prioritize mitigation projects in the next phase of the planning

process, you may find it necessary to gather the additional information in order to perform a benefit-cost analysis.

____

If you wish to end your inventory collection at this point

Go to Summary (page 3-13)

____

Task C. Compile a detailed inventory of what can be

damaged by a hazard event.

You will now begin to develop a more detailed inventory of the

types of assets that are located in hazard areas, and the characteristics of those assets. Collecting data on these characteristics will help

you determine the losses to these assets from different hazards.

1. Determine the priorities for your inventory collection efforts.

After you have determined for which hazard events you will gather

additional information, you will determine your priorities for

collecting the information. Choices about how much information

you can reasonably gather may be particularly important for large

communities or for areas with a dense concentration of assets. In

some cases, the hazard profiles created in Step 2 will have already

helped focus your efforts by eliminating areas without a significant

hazard threat from your immediate concern.
inventory assets 3

Version 1.0 August 2001 3-9

Following are some ideas on how to focus your time and money on

the most urgent and important elements within your community or

state.

 Identify critical facilities that are important to your

community or state. (See the definitions above).

 Identify vulnerable populations such as non-English

speaking people or elderly people who may require

special response assistance or special medical care after a

disaster.

 Identify economic elements such as major employers and

financial centers in your jurisdiction that could affect the

local or regional economy if significantly disrupted.

 Identify areas with special considerations such as areas of

high-density residential or commercial development that,

if damaged, could result in high death tolls and injury

rates.

 Identify historic, cultural, and natural resource areas

including areas that may be identified and protected

under state or federal law.

 Identify other important facilities which help ensure a

full recovery of your community or state following a

hazard event. These would include: government funcHAZUS separates critical buildings and facilities

into the five categories shown below based on their loss potential. For

the purpose of this guide, all of the following elements are considered

critical facilities:

Essential Facilities are essential to the health and welfare of the whole

population and are especially important following hazard events. The potential consequences of losing them are so great, that they should be carefully

inventoried. Be sure to consider not only their structural integrity and content

value, but also the effects on the interruption of their functions because the

vulnerability is based on the service they provide rather than simply their

physical aspects. Essential facilities include hospitals and other medical facilities, police and fire stations, emergency operations centers and evacuation shelters, and schools.

Transportation Systems include airways – airports, heliports; highways –

bridges, tunnels, roadbeds, overpasses, transfer centers; railways – trackage, tunnels, bridges, rail yards, depots; and waterways – canals, locks,

seaports, ferries, harbors, drydocks, piers.

Lifeline Utility Systems such as potable water, wastewater, oil, natural gas,

electric power and communication systems.

High Potential Loss Facilities are facilities that would have a high loss

associated with them, such as nuclear power plants, dams, and military

installations.

Hazardous Material Facilities include facilities housing industrial/hazardous materials, such as corrosives, explosives, flammable materials, radioactive materials, and toxins.
3-10 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

tions, major employers, banks, and certain commercial

establishments, such as grocery stores, hardware stores,

and gas stations.

2. Gather building-specific information about the assets.

You will gather building-specific information regardless of the

hazard that you are assessing. The list below discusses the type of

information needed to calculate potential losses from different

hazards in Step 4. You may want to gather this information for all of

your hazards in combination with the hazard-specific information

listed in the next step.

a. Determine the size of the building. Measured by the

square foot, the size of the buildings is used to estimate

both the replacement and function value of buildings.

Sources of information include the tax assessment,

building, zoning, or planning departments.

b. Determine the replacement value. This is usually expressed in terms of cost per square foot and reflects the

present-day cost of labor and materials to construct a

The average replacement values were adjusted by the Consumer Price

Index (CPI) to represent 2000

dollar figures.

The CPI is the ratio of the value of a basket of goods in the current year to the

value of that same basket of goods in the

previous year. It measures the average

level of prices of the goods and services

typically consumed by an urban American family. The http://woodrow.mpls.frb.fed.

us/research/data/us/calc/hist1800.cfm

Website can be used to adjust historic

dollar figures to current year dollar figures.

tnemecalpeRgnidliuBegarevA

tooFerauqSrepeulaV

ssalCycnapuccO latoT

.tf.qs/$

gnillewDylimaFelgniS 77

emoHeliboM 25

gnillewDylimaf-itluM 89

gnigdoLyraropmeT 201

yrotimroDlanoitutitsnI 89

emoHgnisruN 98

edarTliateR 76

edarTelaselohW 35

secivreSriapeR/lanosreP 29

secivreS.hceT/lanoisseforP 78

sknaB 151

latipsoH 541

cinilC/eciffOlacideM 211

noitaerceR&tnemniatretnE 131

sretaehT 89

gnikraP 03

lairtsudnIyvaeH 96

lairtsudnIthgiL 96

slacimehC/sgurD/dooF 96

gnissecorPslareniM/slateM 96

ygolonhceThgiH 96

noitcurtsnoC 96

erutlucirgA 62

seciffOtiforP-noN/hcruhC 311

secivreSlareneG 88

esnopseRycnegremE 031

sloohcS 19

seitisrevinU/segelloC 511

Source: HAZUS

The type of hazard

event will influence what

information should be gathered in the inventory. In Steps

1 and 2 it became apparent

that because there are fundamental differences in the hazard types, there are

corresponding differences in the type of

information and data you are collecting.

For example, floodwaters tend to inundate whatever is within a given area to a

known consistent depth. However, hazard events such as tornadoes that are

equally likely to occur anywhere in the

community are usually profiled in terms

of the magnitude (e.g., wind speed).

Therefore, for hazard events such as

floods, the information gathered will be

based on the geographic area expected

to be flooded, based on past experience.

For a less predictable hazard such as a

tornado, you will be less concerned with

specific location; instead, you will focus

on the construction characteristics for

buildings throughout the community.
inventory assets 3

Version 1.0 August 2001 3-11

Contents Value as Percentage of Building Replacement Value

Occupancy Class Contents Value (%)

Residential (including temporary lodging, dormitory, and

nursing homes) 50

Commercial (including retail, wholesale, professional,

services, financial, entertainment & recreation) 100

C hd ommercial (including o ml spital an e o/ dica fc) fice l 0 inic 15

C 0 ommercial Parking 5

I 0 ndustrial (including heavy, light, technology) 15

I 0 ndustrial Construction 10

A 0 griculture 10

R 0 eligion/Non-Profit 10

G 0 overnment Emergency Response 15

G 0 overnment General Services 10

E 0 ducation Schools/Libraries 10

E 0 ducation Colleges/Universities 15

Source: HAZUS

building of a particular size, type, and quality. The

replacement value is the current cost of returning a

physical asset to its pre-damaged condition.

If you do not already have the replacement values

from HAZUS or a local source use the table to the left

and find the average replacement values per square foot.

These costs are based on national averages for materials

and installation and may need to be adjusted to account

for regional differences. For example, building materials

and supplies cost more in Hawaii than Kansas. Finally,

multiply the cost per square foot by the size (in square

feet) of the building you are

assessing.

c. Determine the content value.

If you do not already have

the estimated content values

from HAZUS or a local

source, use the table at right

to estimate the content

value. Find the type of

building you are assessing

and determine the percent of

the content replacement

value. Multiply this percent

by the building replacement

value to calculate the content

replacement value. Although

there is not a standard cost

variation table, you should

keep in mind that some contents such as antiques or

collectibles may be worth more than the average values.

Increase your estimated content loss for these types of

contents as you deem necessary.

d. Determine the function use or value. This represents the

value of a building's use or function that would be lost if

it were damaged or closed. A standard way to calculate

the monetary damage from losing public functions is to

use the budget of the service as a proxy for its value to

the community. For private functions, the table on page

3-12 shows the average annual sales or production based

on square footage. Using the table, find the type of

function you are assessing and multiply the index by the

structure size. The damages from "loss of function" are

often much greater than physical damage to a structure.
3-12 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Example 1

To find the annual sales from

a 15,000 square foot grocery

store, you would multiply the

structure size by $30 per square foot

(from the table at right).

15,000 x $30

The annual sales would be $450,000.

Example 2

If a public library will be lost for three

months due to damage from a 100-year

flood, you could determine the damages

from the loss of function by multiplying

the monthly budget of the library (overhead, rent, staff salaries, etc.) by three

months.

e. Determine the displacement cost. The displacement cost

is the dollar amount it would cost for the function

(business or service) to be relocated to another structure

because of a hazard event. These costs include rent for

temporary building space per month, one-time displacement costs to set up operations in the new space, lost

rent per month from all tenants, and other costs of

displacement.

f. Determine the occupancy or capacity. Determine how

many people the asset, such as a building or bridge, is

designed to hold or service. Building capacities are

available from local fire departments and/or fire

marshal's offices. Bridge load ratings can be obtained

from the responsible local, state, or federal transportation departments.

3. Gather hazard-specific information about the assets.

The pages that follow discuss the type of information needed to

calculate potential losses from different hazards in Step 4. Because

the characteristics of different hazards create the need for different

types of data, you should review your unique combination of hazards to determine how you may want to approach data collection.

The following table illustrates how different hazards may require

different data.

Annual Gross Sales or Production (Dollars per Square Foot)

Occupancy Class A t nnual Sales ($ / f 2)

Commercial

R 0 etail Trade 3

W 3 holesale Trade 4

Industrial

H 0 eavy 40

L 7 ight 12

F 1 ood/Drugs/Chemicals 39

M 8 etals/Minerals Processing 36

H 5 igh Technology 24

C 1 onstruction 43

Agriculture

A 3 griculture 8

Source: HAZUS
inventory assets 3

Version 1.0 August 2001 3-13

Summary

After you have completed Step 3, you will know the quantity of

buildings, people, and building values that lie in the different

hazard areas and what proportion of the community this represents.

If you decided to develop a more detailed inventory of what lies in

these hazard areas, you will also know about many of the characteristics of the buildings and population. This will enable you to

estimate losses resulting from hazard events and to determine where

to best begin to address mitigation issues and focus your resources.

Above all, you now have a better understanding of what is at risk in

your community and an emerging picture of what your community

stands to lose after a hazard event.

Step 3 most likely will present the greatest challenge in the loss

estimation process and has the greatest potential to be a resource

drain, but it is actually the most meaningful step. The degree to

which you invest time and resources in the inventory will determine

the quality of the loss estimation in Step 4, and ultimately your

ability to prioritize mitigation actions during the next phase of the

planning process.

____

If you have completed your inventory

Go to Step 4

to estimate the losses.

____

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation   

Building Code Design Level /

Date of Construction

    

Roof Material  

Roof Construction  

Vegetation 

Topography   

Distance from the Hazard Zone    
3-14 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

The Hazardville Post

Vol. CXI No. 256 Thursday, September 13, 2001

Hazardville Risk Assessment Back On Track

(Part 3 of a 4 part series on the Risk Assessment Process)

[Hazardville, EM] Town Council members held a special meeting Monday,

upset that the inventory had not yet been

completed. Joe Norris, the lead planner

of the Town of Hazardville Organization

for Risk Reduction (THORR), testified

that the task force has been working since

April to collect data on the hazards that

could potentially affect Hazardville and

assess the effects of those hazards on

the town. Norris explained that collecting the initial information on the town

and the hazards went fairly quickly.

Norris said, "The initial inventory

was simplified due to the assistance offered by the State of Emergency Hazard Mitigation Officer." To get the ball

rolling, the State of Emergency Office

of Emergency Preparedness (EOEP),

used a loss estimation tool developed

by the Federal Emergency Management

Agency, Hazards U.S. (HAZUS) to provide an initial inventory of critical facilities and buildings in the community.

This information was added to the base

map and assessed against each of the

hazard zones. The final tally from the

HAZUS inventory is shown in Table 1.

The slowdown came when the

THORR reviewed the initial numbers and

realized just how much and what was located in the hazard zones. Norris exclaimed, "Do you realize that all five

commercial establishments and the only

industrial plant in the Town of Hazardville

can be impacted from four different hazards, and four out of the five business

can be impacted by a fifth hazard?" The

school, which substitutes as an emerTable 1: HAZUS Inventory Totals

Occupancy

Class

TOTAL

ASSETS Flood Earthquake* Tsunami CoastalStorm

Tornado* Wildfire Landslide

Residential 6 ) 2 1 2 6 (25% 6 ) 3 ) (4.8% 1 2 8 (29% 6 ) 1 ) 9 (30.6% 2 (3.2%

Commercial 5 ) 45 ) (80% 5 ) (100% 5 50 0 (100%

Industrial 10 1 ) 1 ) (100% 1 10 0 (100%

Agricultural 2 ) 1 20 ) (50% 12 ) (100% 2 ) (100% 2 (100%

Religion/

Non-Profit 4 ) 14 ) (25% 2 ) (50% 4 40 ) (100% 2 (50%

Government 7 ) 47 ) (57% 1 ) (14% 77 ) (100% 5 ) (71% 1 (14%

Education 1 ) 11) (100% 1 ) (100% 1 10 (100%

Number of

Buildings

82 31

(37.8%) 82 14(17%)

41

(50%) 82 29(35%)

6

(7.3%)

Approximate

Value ($M) 34.357 12.334

(35.8%) 34.357 12.396(36%)

21.520

(62.6%) 34.357 6.641(19%)

3.900

(11%)

Number of

People 4 ) 13 7 3 4 (18% 4 ) 1 9 ) (2.2% 1 3 65 (40% 4 ) 1 2 ) 9 (7% 19 (4.6%

* These hazards are random in nature and could affect any portion or the whole town.

Source: State of Emergency Office of Emergency Preparedness – HAZUS.

(see Risk, page 3-15)
inventory assets 3

Version 1.0 August 2001 3-15

gency shelter, is vulnerable to five of

seven hazards. In addition, over $21 million dollars in assets are vulnerable to

coastal storms alone, including the police/fire department.

Based on the HAZUS data, THORR

unanimously voted in favor of gathering

additional inventory data on all of the

town's critical facilities, as well as the

historic lighthouse and buildings that

have been flooded more than twice.

Norris explained, "The THORR realized

that more data was needed in order to

determine where the highest loss could

occur or what should be our top priority

Risk (continued from page 3-14)

for mitigation; however, inventorying

each of the buildings had been more

time consuming than anticipated and

identifying the number of buildings in

the various hazard areas quickly overwhelmed the volunteers."

So, in addition to working with the

EOEP, THORR worked with numerous

volunteer and community groups to complete the inventory. The local Girl Scout

troop verified the location of all the

buildings in the 100-year floodplain, and

the volunteer fire department conducted

a sidewalk survey to inventory the wildfire hazard area, including the Clearview

Acres Subdivision. Members of the

University Geology Club inventoried the

landslide hazard areas, and the department of Public Works received training

in Rapid Visual Screening for seismic

and wind vulnerability and inventoried

all public buildings for earthquakes and

tornadoes.

According to Norris, the final results of the loss estimation should be

available in about two months after they

complete the final step of estimating

losses.

Hazardville Risk Assessment
3-16 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task C. Compile a more detailed inventory of what can

be damaged by a flood hazard event.

1. Determine priorities for your inventory collection efforts.

In large communities, you may choose to prioritize your inventory

by selecting the more hazardous floodplains (based on Step 2) first,

by starting with the older buildings, critical facilities, or the assets

that are closest to the flood hazard such as those in the floodway.

For example, buildings that were constructed before local or state

floodplain ordinances went into effect will most likely not be

elevated to or above the expected flood level, and are most susceptible to flood damage. Buildings whose structures or contents are

most susceptible to flood damage, such as wood frame buildings,

manufactured homes, or buildings with delicate contents or expensive machinery are also more vulnerable to flood damage. You

should also identify repetitive loss properties as part of this activity.

2. Gather building-specific information about the assets.

Gather the building-specific information including size, replacement value, content value, function use or value, displacement cost,

occupancy or capacity. For more information refer to Task C,

number 2 on page 3-10.

Under NFIP guidelines,

repetitive loss structures include any currently insured building with

two or more flood losses (occurring more than ten days

apart) greater than $1,000 in

any 10-year period since

1978.

States should provide communities

with information on

historic floods throughout the

state so communities will

know what type of damage has occurred

(even if it didn't occur within that particular community).

States should ensure that lists of repetitive loss properties are kept up to date

and that communities have the most current list. States should contact their

FEMA Regional Office for this information.

FEMA also maintains a national list of

properties that comprise the “Repetitive

Loss Target Group”. These are repetitive

loss properties that have either experienced four or more losses with the characteristics above, or have had losses

that cumulatively exceed the property

value of the building.

Floods
Version 1.0 August 2001 3-17

inventory assets 3

3. Gather hazard-specific information about the assets.

In addition to the items shown in the table below, the following

information will be used later in Step 4 to determine flood vulnerability:

 Lowest floor elevation. Identify the elevation of the

lowest floor of the lowest enclosed area (including

basement). This information can be obtained from an

elevation certificate (found in the office of the local

NFIP administrator, who also often serves as the local

building official or planner) if the building was constructed after your floodplain management ordinance

was in force. It may also be available from a recorded

subdivision plat, site survey, or building permit.

A basic approach to

estimating the lowest floor elevation is to estimate the elevation for a whole block of

similarly located buildings.

You may also consider generalizing your

inventory by making an assumption that

buildings constructed after the FIRM was

published are above the base flood elevation and buildings constructed prior

to the FIRM are below the base flood elevation.

If a lowest floor elevation has not been

recorded, it can be determined in a number of ways.

The most accurate way is to

hire a professional land surveyor to fieldmeasure the lowest floor elevation from

a local surveying benchmark or other

point of known elevation. Other less accurate methods include measuring (such

as with a hand level) from a nearby

benchmark, a neighbor's property that

has been surveyed, or any other point of

known elevation. Also, property owners

who have experienced prior flooding may

have marked the water level on the building. These property owners can check

local records for the elevation of the flood

during that storm and estimate the lowest-floor elevation relative to their highwater mark.
3-18 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

 Base Flood Elevation. The base flood elevation is the

elevation (referenced to a datum) of the flood having a

one percent chance of being equaled or exceeded in any

given year. This information can be found on the FIRM

and flood profile. The following diagram shows how to

find the BFE at a given point in the floodplain.

To determine the BFE

using the FIRM:

c locate a feature(s) on the FIRM,

near the site you are assessing,

that also appears on the FIS Flood

Profile, such as a bridge, highway,

or cross-section.

d Calculate the distance from the

feature along the stream to the site

you are assessing using the scale

used on the FIRM.

e Locate the site you are assessing

on the FIS Flood Profile by using

the scale on the FIS to measure the

distance from the feature to the site.

f Follow a vertical line up to the water

surface line on the Flood Profile.

g Follow a horizontal line to the y-axis

to read the elevation.
Version 1.0 August 2001 3-19

inventory assets 3

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation   

Building Code Design Level /

Date of Construction

    

Roof Material  

Roof Construction  

Vegetation 

Topography   

Distance from the Hazard Zone    

____

Go to the next hazard on your list to

inventory

or if you are finished with all your hazard inventories

Go to Step 4

____
3-20 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task C. Compile a more detailed inventory of what can

be damaged by an earthquake hazard event.

1. Determine priorities for your inventory collection efforts.

Determining inventory priorities for earthquakes requires consideration of the potential intensity of the earth movements. For example, some buildings, such as those constructed of unreinforced

masonry, perform very poorly in earthquakes. In addition, buildings

constructed prior to seismic building code requirements or under

low seismic building codes will also perform poorly in earthquakes

of a given intensity. With this in mind, you might choose to inventory only those at first, to see what risks are evident before proceeding with a full inventory. This can be accomplished through a

seismic evaluation of your buildings.

This method of selecting elements with the most apparent vulnerability determines whether there is sufficient vulnerability to justify

additional evaluations. For example, if you initially include in your

inventory only those buildings that would do poorly in an earthquake of a known intensity and/or those with high occupancy and

conclude that there is still not much risk, you may wish to assume

that other types of buildings or structures will be at even lower risk.

Earthquakes

Code Seismic

Design Level

States and communities

change their building codes

over time as more is learned

about hazards and construction techniques. The determination of high, moderate, or low code levels can be

considered subjective. You should talk

with your local and/or state code officials

to determine this aspect of vulnerability.

For example, in areas of high seismicity

(e.g., coastal California), buildings of

newer construction (e.g., post-1973) are

best represented by High-Code damage

functions, while buildings of older construction would be best represented by

Moderate-Code damage functions, if built

after about 1940, or by Pre-Code damage functions, if built before about 1940

(i.e., before seismic codes existed). PreCode damage functions are appropriate

for modeling older buildings that were not

designed for earthquake load, regardless

of where they are located in the United

States.

NEHRP Handbook for the Seismic Evaluation of

Existing Buildings (FEMA 178) presents a nationally applicable

method for engineers to identify buildings or building components that

present unacceptable risks in an earthquake. Four structural subsystems

in which deficits may exist are identified:

Vertical elements resisting horizontal loads;

Horizontal elements resisting lateral loads;

Foundations; and

Connections between structural elements or subsystems.

Rapid Visual Screening of Buildings for Potential Seismic

Hazards: A Handbook (FEMA 154) and Supporting Documentation (FEMA

155) present a method for quickly identifying buildings posing risk of death, injury,

or severe curtailment in use following an earthquake. Trained personnel can use

the methodology known as "Rapid Screening Procedure (RSP)" to identify potentially hazardous buildings. This identification is based on a 15- to 30-minute exterior

inspection, using a data collection form included in the handbook. Twelve basic

structural categories are inspected, leading to a numerical "structural score" based

on visual inspection. Building inspectors are the most likely group to implement an

RSP, although this report is also intended for building officials, engineers, architects, building owners, emergency managers, and interested citizens. The supporting documentation reviews the literature and existing procedures for rapid visual

screening.
Version 1.0 August 2001 3-21

inventory assets 3

2. Gather building-specific information about the assets.

Gather the building-specific information including size, replacement value, content value, function use or value, displacement cost,

occupancy or capacity. For more information refer to Task C,

number 2 on page 3-10.

3. Gather information about the assets.

In addition to the information shown in the table below, the

following information will be needed to determine earthquake

vulnerability as part of Step 4:

 Seismic design building code. One aspect of structure

vulnerability is based on building codes. Older buildings

constructed under a low seismic design building code or

without any seismic considerations are more vulnerable

to earthquakes of a given intensity than buildings constructed to a high or moderate seismic design building

code. Determine the level (high, moderate, low, or precode) of seismic design building code that is currently in

effect, when it went into effect, and what levels of

seismic codes have been in effect in the past. Based on

this information work with your building code department to determine under which code the buildings in

your inventory were designed. Keep in mind that buildings built under a code with low seismic design provisions

could have been subsequently retrofitted under a more

stringent code.

If you are using

HAZUS to estimate

your earthquake

losses, these calculations

will be completed within the

program.

Using HAZUS to

identify buildings

constructed before the adoption of seismic building codes

can help you quickly identify

buildings that will be vulnerable to earthquakes.

Intensity is a subjective measure of the strength of the shaking

experienced in an earthquake. Intensity is based on the observed

effects of ground shaking on

people, buildings, and natural features. It varies from place to place within the disturbed

region depending on the location of the observer with respect to the earthquake epicenter. The "intensity" reported at different points

generally decreases away from the earthquake epicenter. Local geologic conditions

strongly influence the intensity of an earthquake; commonly, sites on soft ground or alluvium have intensities 2 to 3 units higher than

sites on bedrock. The Modified Mercalli

Scale represents the local effect or damage

caused by an earthquake.

It is possible to relate the PGA value you identified in Step 2 to the Mercalli scale. (See table.)

Modified Mercalli Intensity and PGA Equivalents

MMI Acceleration (%g)

(PGA)

Perceived Shaking Potential Damage

I < 0.17 Not Felt None

II 0.17 - 1.4 Weak None

III 0.17 - 1.4 Weak None

IV 1.4 - 3.9 Light None

V 3.9 - 9.2 Moderate Very Light

VI 9.2 - 18 Strong Light

VII 18 - 34 Very Strong Moderate

VIII 34 - 65 Severe Moderate to Heavy

IX 65 - 124 Violent Heavy

X > 124 Extreme Very Heavy

XI > 124 Extreme Very Heavy

XII > 124 Extreme Very Heavy

Source: USGS
3-22 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

____

Go to the next hazard on your list to

inventory

or, if you are finished with all your hazard inventories

Go to Step 4

____

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation   

Building Code Design Level /

Date of Construction

    

Roof Material  

Roof Construction  

Vegetation 

Topography   

Distance from the Hazard Zone    
Version 1.0 August 2001 3-23

inventory assets 3

Task C. Compile a more detailed inventory of what can

be damaged by a tsunami hazard event.

1. Determine priorities for your inventory collection efforts.

If your community has a relatively small tsunami area, you may

decide to inventory all of the assets inside the hazard boundary on

your base map. If you have a large tsunami area or if numerous

buildings are located inside the hazard boundary, you may decide to

prioritize your inventory by starting with those closest to the shoreline, and critical facilities.

2. Gather building-specific information about the assets.

Gather the building-specific information including size, replacement value, content value, function use or value, displacement cost,

occupancy or capacity. For more information refer to Task C,

number 2 on page 3-10.

3. Gather information about the assets.

After you have made a list of all the assets located inside the tsunami hazard area, you will need to gather information shown in the

table below.

Tsunamis

____

Go to the next hazard on your list to

inventory

or, if you are finished with all your hazard inventories

Go to Step 4

____

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation    

Building Code Design Level /

Date of Construction

    

Roof Material  

Roof Construction  

Vegetation 

Topography   

Distance from the Hazard Zone    
3-24 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task C. Compile a more detailed inventory of what can

be damaged by a tornado hazard event.

1. Determine priorities for your inventory collection efforts.

Since tornadoes can possibly affect the whole community or state, it

is very important to set some priorities because inventorying everything could be very labor and time intensive. If necessary, communities and states should narrow their inventory to assets that are of

particular importance from a public safety, historical, economic, or

environmental standpoint.

Communities that want to begin by identifying the assets that are

not built to withstand the design wind speed, or assets that typically

get damaged in tornadoes should examine the date of construction.

For example, buildings that were constructed before local or state

building codes went into effect, and/or buildings built to codes

whose wind speed standards are below those indicated on the

Design Wind Speed map shown below are more vulnerable to

tornadoes.

Tornadoes

Meteorologists use

the Fujita scale to determine

the intensity of tornadoes.

Most tornadoes are in the F0-

F2 class. Building to modern

wind standards provides significant property protection from these hazard events;

however, a community in the direct path

of a violent tornado may experience extensive damages. Designing buildings to

extreme wind speeds, such as those associated with an F-3 or greater tornado

is beyond the scope of current building

codes.

The Building Performance Assessment

Report for the Oklahoma and Kansas

Tornadoes (FEMA 342) includes a good

description of tornadoes and associated

damage.

Communities should build new shelters

or reinforce existing shelters to withstand

the design wind speeds described in

Step 2.

* Design Wind Speed measuring criteria 

 are consistent with ASCE 7-98

 – 3-second gust

 – 33 feet above grade

 – Exposure C
Version 1.0 August 2001 3-25

inventory assets 3

2. Gather building-specific information about the assets.

Gather the building-specific information including size, replacement value, content value, function use or value, displacement cost,

occupancy or capacity. For more information refer to Task C,

number 2 on page 3-10.

3. Gather information about the assets.

After you have made a list of all the assets you wish to include inside

the tornado hazard area, you will need to gather the information

shown in the table below.

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation   

Building Code Design Level /

Date of Construction

   

Roof Material  

Roof Construction  

Vegetation 

Topography   

Distance from the Hazard Zone    

____

Go to the next hazard on your list to

inventory

or if you are finished with all your hazard inventories

Go to Step 4

____
3-26 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task C. Compile a more detailed inventory of what can

be damaged by a coastal storm hazard event.

1. Determine priorities for your inventory collection efforts.

In addition to identifying critical facilities, you may further prioritize your inventory items by starting with buildings and other assets

closest to the coastal storm hazard area or at the lowest elevations

and prone to the highest potential flood and tidal surge levels, wave

velocities, and erosion hazards.

Because hurricane-strength winds would likely affect whole communities or large portions of your state, conducting an inventory of

every building subject to coastal storm winds would be very time and

labor intensive. Therefore, if necessary, you should identify solely

buildings or areas that may be more prone to wind hazards. The

condition, age, and primary building materials can be indications of

the building's physical vulnerability to wind and water hazards.

Knowing the wind provisions of the building code and the floodplain management regulations in effect at the time of construction

are essential in determining buildings' vulnerability to coastal

storms.

Identify the assets that may be exposed to coastal storm hazards

according to your priority system. For example, buildings or structures built before local floodplain ordinances went into effect most

likely will not be elevated to or above the expected flood level or

Coastal flooding, high

winds, and often erosion will

affect the coastal storm hazard area in your community.

Keep in mind that the flood

zones and boundaries shown on the

FIRM are based on conditions at the time

the study was completed. As shoreline

erosion occurs, the location of these

zones and boundaries will change. For

example, the red house, currently in Zone

AE may be located in Zone VE within 30

years and the green house, currently out

of the floodplain entirely, may be located

in Zone AE within 30 years.

Coastal Storms
Version 1.0 August 2001 3-27

inventory assets 3

may have obstructions or an enclosed space below the elevated

structure making them most susceptible to flood, wind, or storm

surge damage. Also, buildings or structures built on high bluffs

above the oceans or high cliffs such as those along the Great Lakes

are susceptible to erosion of the land beneath the foundation.

Once the erosion reaches the foundation, the house will be lost or

damaged sufficiently to become uninhabitable.

2. Gather building-specific information about the assets.

Gather the building-specific information including size, replacement value, content value, function use or value, displacement cost,

occupancy or capacity. For more information refer to Task C,

number 2 on page 3-10.

3. Gather Information about the assets.

In addition to the items listed in the table on the next page, the

following information will be used in Step 4 to determine vulnerability to coastal storms:

 Lowest floor elevation. For V zones, the relevant elevation is that of the bottom of the lowest horizontal

structural member, NOT the top of the lowest finished

floor as used in non-coastal flood assessments. This

definition is used for consistency with NFIP minimum

floodplain management requirements.

This information can be obtained from an elevation

certificate if the building was built after your

community's floodplain management ordinance was in

force. It also may be available from a recorded subdivision plat, site survey, or building permit.

A basic approach to

estimating the lowest floor elevation is to estimate the elevation for a whole block of

similarly located buildings.
3-28 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation   

Building Code Design Level /

Date of Construction

    

Roof Material   

Roof Construction   

Vegetation 

Topography   

Distance from the Hazard Zone    

 Base Flood Elevation. The base flood elevation is the

elevation (referenced to a datum) of the flood having a

one percent chance of being equaled or exceeded in any

given year. This information can be found on the FIRM.

____

Go to the next hazard on your list to

inventory

or, if you are finished with all your hazard inventories

Go to Step 4

____
Version 1.0 August 2001 3-29

inventory assets 3

Landslides

Task C. Compile a more detailed inventory of what can

be damaged by a landslide hazard event.

1. Determine priorities for your inventory collection efforts.

Landslides usually affect infrastructure such as roads and bridges,

but they can also affect individual buildings and businesses. If your

community has a relatively small landslide area, you may decide to

inventory all of the assets inside the hazard boundary on your base

map. If you have a large landslide area or if numerous buildings are

located inside the hazard boundary, you may decide to prioritize

your inventory by starting with the critical facilities.

2. Gather building-specific information about the assets.

Gather the building-specific information including size, replacement value, content value, function use or value, displacement cost,

occupancy or capacity. For more information refer to Task C,

number 2 on page 3-10.

3. Gather information about the assets.

After you have made a list of all the assets located inside the landslide hazard area, gather the data listed in the table below.

____

Go to the next hazard on your list to

inventory

or if you are finished with all your hazard inventories

Go to Step 4

____

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation   

Building Code Design Level /

Date of Construction

    

Roof Material   

Roof Construction   

Vegetation 

Topography    

Distance from the Hazard Zone    
3-30 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task C. Compile a more detailed inventory of what can

be damaged by a wildfire hazard event.

1. Determine priorities for your inventory collection efforts.

If your wildfire hazard area is relatively small, you may decide to

inventory all of the assets within your wildfire hazard boundary on

your base map. If you have a large wildfire hazard area or if you

have many assets within your hazard area, you may decide to

prioritize your inventory by starting with the critical facilities. You

can also prioritize by first inventorying the extreme wildfire hazard

area and then as time and money permit, inventorying the high

and moderate hazard areas.

Information about buildings that were constructed before local or

state fire codes were adopted or upgraded can be gathered from the

building permit or planning office.

2. Gather building-specific information about the assets.

Gather the building-specific information including size, replacement value, content value, function use or value, displacement cost,

occupancy or capacity. For more information refer to Task C,

number 2 on page 3-10.

3. Gather Information about the assets.

After you have made a list of all the assets located inside the wildfire

hazard area, gather the data listed in the table below.

Wildfires

Building Data Requirements By Hazard

Building Characteristics Flood Earthquake Tsunami Tornado Coastal Storm Landslide Wildfire

Building Type / Type of Foundation   

Building Code Design Level /

Date of Construction

    

Roof Material   

Roof Construction   

Vegetation 

Topography   

Distance from the Hazard Zone    
Version 1.0 August 2001 3-31

inventory assets 3

____

Go to the next hazard on your list to

inventory

or if you are finished with all your hazard inventories

Go to Step 4

____

Click to proceed to

Step 4

Return to

Table of Contents
step
4

Version 1.0 August 2001 4-1

estimate

losses

Overview

The fourth step in the loss estimation process answers the question: How will the community’s assets be affected by the hazard event?

So far, you have determined that one or more hazards may affect

your planning area (Step 1), profiled the hazard events (Step 2),

and inventoried the assets that can be damaged by the hazard event

(Step 3). In this step, you will bring this information together to

estimate your losses in terms of the expected losses from hazard

events to people, buildings, and other important assets. Some

buildings, infrastructure, or functions will be damaged more than

others in the same hazard event because they are more vulnerable—their location or construction makes them more susceptible

to damage from the hazard event. For example, two bridges of

similar construction that are exposed to the same flood hazard

event may experience different levels of damage. One bridge may

be built to lower construction standards, be older, or have a lower

elevation, thus suffering greater damage than the other bridge.

Remember, a true “risk assessment” takes into account all of the

possible hazard events rather than just a single event. For the

purpose of this planning guide, the

losses will be calculated from a selected hazard event.

To complete the loss estimation, you

will first assess the level of damage

from a hazard event, both as a percentage of the asset’s structural and

content replacement value and as a

function. To illustrate, your investigation may find that in a 100-year flood

event, a particular building could

suffer damage at a level equal to 50

percent of its total value. Next, you

will calculate the potential loss by

multiplying the value of the structure,

contents, or use that you gathered in

The most convenient way to express

the expected losses

is in terms of dollars. This will

provide a relative ranking of

risk to different elements of the planning

area from different hazards. They are extremely rough estimates that should not

be used for any other purpose.

If you conducted an abbreviated inventory in Step 3,

you will not assess the level of damage for each asset in the inventory (Task

A). Instead, you will determine a level of damage from each hazard

for the entire hazard area using historical evidence of damage and

data on population growth.

For example, assume that in Step 1, you discovered that a flood in

1955 caused $1,000,000 in damages and affected 1,000 residents

in the floodplain. In the years since the 1955 flood, census data

reveal that the community population has grown 70 percent. By comparing

aerial photographs of the same area taken in the 1950’s and in the 1990’s, you

estimate that floodplain development has increased by 50 percent. Therefore,

you conclude that the same flood today would cause $1,500,000 in damage,

or rather, $9,881,423 when adjusted to 2001 dollars. In addition, you estimate

the number of affected residents would be about 1,700.

If you discovered in Steps 1 and 2 that you are threatened by a hazard that

has not occurred in recent memory, then you can base your estimate of risk

on some general rules of thumb identified in the hazard specific sections which

follow.

After you have estimated the amount of damage and number of affected residents for your abbreviated inventory, skip to Task B to complete Step 4.

This elementary school suffered

devastating losses during tropical

storm Alberto in 1994.
4-2 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Hazard _______________________________________

Worksheet #4 Estimate Losses step 

Date: October, 2001 How will these hazards affect you?

Historic Lighthouse

Bridge

Sewage Treatment Plant

STP Outbuilding

STP Outbuilding

Water Treatment Plant

Hospital

Police & Fire Station

1,500,000

750,000

2,500,000

1,000,000

750,000

250,000

2,500,000

2,000,000

18

20

13

13

13

5

5

5

270,000

150,000

325,000

130,000

97,500

12,500

125,000

100,000

$1,210,000

50,000

N/A

2,500,000

1,500,000

1,500,000

250,000

3,750,000

3,000,000

27

N/A

19.5

19.5

19.5

7.5

7.5

7.5

13,500

N/A

487,500

292,500

292,500

18,750

281,250

225,000

$1,611,000

Historic Lighthouse

Bridge

Sewage Treatment Plant

STP Outbuilding

STP Outbuilding

Water Treatment Plant

Hospital

Police & Fire Station

2,191

31,740

82,191

684

684

2,740

2,055

960

7

4

3

2

2

1

0

1

500

12,000

200,000

5,000

1,000

2,000

2,500

2,000

2

4

3

2

2

0

0

0

16,337

174,960

846,573

11,368

3,368

2,740

0

960

$1,056,306

299,837

324,960

1,659,073

433,868

393,368

33,990

406,250

325,960

$3,877,306

Flood
estimate losses 4

Version 1.0 August 2001 4-3

A loss estimation table is a

projection of likely damage by

magnitude of the hazard (expressed as a percentage of

replacement cost), based on

observed past damages.

Step 3 by the percent of damage expected from the hazard event. It

is important to remember that a comprehensive loss estimation

should include the contents and functions of the buildings in

addition to the risk to the structure itself. Also, please note that this

can become more complex as you attempt to account for a wider

range of possible effects from one or more hazards. Therefore, you

should use Worksheet #4: Estimate Losses in Appendix C(see

example on page 4-2) to keep track of your results. If you used a

computerized spreadsheet or GIS database for your inventory in

Step 3, then you may want to continue to use that same method for

this step.

Procedures & Techniques

Task A. Determine the extent of damages.

The hazard-specific sections that follow will help you estimate the

potential losses to your assets from the hazards that can affect you.

You will find that some of the hazards have definitive loss estimation

tables while others do not. In the cases where loss estimation tables

are not currently available, you can use the full value of the assets

that are in the hazard area, or base your assumptions on your past

experiences with those hazards in your planning area. For example,

if your planning area is susceptible to wildfires and you inventoried

all of the assets that can be damaged by a wildfire, then you would

assess the vulnerability by estimating the number of assets that

would be destroyed in a wildfire based on past wildfires.

1. Estimate the losses to structures.

Determine how the various hazard events will affect the structures

within your planning area. Use the structure loss estimation tables

to determine the estimated percent of damage from the various

hazard events. The estimated damages are expressed as a percentage of structure replacement value. Multiply the structure replacement value (Step 3) by the expected percent damage (provided in

the hazard-specific sections that follow) to determine the loss to the

structure in a particular hazard event.

For example, if the library’s structure replacement value equals

$100,000 and the expected damage from a 100-year flood is 40

percent of the structure, then the loss to this structure from a flood

is $40,000.

2. Estimate the losses to contents.

Determine the expected amount of damage to the contents of the

structures you inventoried. Multiply the replacement value of the

In this how-to guide

floods, earthquakes, and

coastal storms have loss estimation tables (tornadoes,

landslides, tsunamis, and

wildfires do not). These tables are from

various sources including the Means

Square Foot Cost publication, HAZUS,

and FEMA’s Benefit-Cost Analysis module. They have been simplified and represent generalized information. For more

detailed analysis, go to the source listed

for each table.

Loss to structure =

(structure replacement

value) x (percent damage)

Loss to contents =

(content replacement value)

x (percent damage)
4-4 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Functional downtime may also be associated with a bridge, road, or

utility that can be damaged by

a hazard, and each of their

several components may have a different associated vulnerability. Consider a

gas pipeline exposed to a wildfire: the

various parts of the gas transmission

system—the piping, the pumps, the monitoring system, and end-distribution

pieces—will likely react differently under

the same level of pressure from the heat

of the wildfire and will have different effects when they fail. If the gas pipeline

fails, the results will probably reach far

beyond physical damages to the pipe –

there could be large-scale business disruption, people might have to leave their

homes, the leaking gas could lead to additional fires, and so on. Use your best

judgment and experience to determine

functional downtime for functions with

many components.

Functional downtime is the average time (in

days) during which a function

(business or service) is unable to provide its services

due to a hazard event.

A basic approach to overcome

limited time or resources is to start by estimating the losses to all the

structures and then, as resources allow, calculate the

content loss, and then the

function loss, etc.

contents (Step 3) by the expected percent damage to determine the

losses to the contents from a particular hazard event.

For example, if the library’s content replacement value equals

$225,000 and the expected damage from a 100-year flood is 10

percent of the contents, then the losses to these contents from a

flood is $22,500.

3. Estimate the losses to structure use and function.

First, you will determine functional downtime, or the time (in days)

that the function would be disrupted from a hazard event. If a

hazard specific loss estimation table is not available, research past

damage in your area and determine the average number of days

various functions were unavailable following a hazard event. Next,

estimate the daily cost of the functional downtime. Divide the

average annual budget or sales (Step 3) by 365 to determine the

average daily operating budget or sales. Multiply the average daily

operating budget or sales by the functional downtime to determine

the cost of the loss of function for the period that the business or

service was unable to operate due to the hazard event.

For example, if an ice cream shop had daily sales of $2,500 during

the summertime and was forced to close for two weeks because of

damages from a hazard event, their function loss would be $35,000

($2,500 x 14 days).

If you are assessing a public facility, such as a library with an annual

budget of $600,000 and an average daily budget of $1,644

($600,000 / 365), you could estimate the losses by using the annual

budget as a proxy for the value of the service to the community. For

example, if the library were closed for seven days due to a flood

event, then the cost for the loss of use for seven days would be

$11,508.

Next, you will determine the displacement time, or the time (in

days) that a function may need to operate from a temporary location due to a hazard event. For example, if the library was closed

for 7 days (functional downtime) and then resumed operations

from an empty trailer for the next 90 days until they could repair

the damages to the existing building, then the displacement time

would be 90 days. Note that not all functions would require displacement before resuming operation.

Multiply the displacement cost (Step 3) by the displacement time to

determine the cost of the displacement from the regular place of

business due to the hazard event.

Displacement time is

the average time (in days) that

the building’s occupants typically must operate from a temporary location while repairs

are made to the original building due to

damages resulting from a hazard event.
estimate losses 4

Version 1.0 August 2001 4-5

When you are determining losses to other kinds of community

functions, such as government services, public works, or business

activity, you use the same procedure. First, determine the cost of loss

of function to the community based on its “normal” condition

(functional downtime cost). Then assess the cost of displacement

because of a hazard event (displacement cost). The sum of these

two numbers will tell you the losses as a result of losing the function

in a particular event.

For example, the losses to the library’s structure, use and function

are the total of the functional downtime costs ($11,508) plus the

displacement costs ($34,400), or $45,908.

4. Calculating human losses.

There are credible estimates available from HAZUS (for earthquakes) and other sources estimating the number of people that

may be hurt or killed in various types of buildings under different

hazard conditions. For the risk assessment it is important to note

that the likelihood of people being injured or killed depends upon

factors such as warning time and the characteristics of the hazard

itself. However, this guide does not place a dollar value on human

lives; rather, you should note areas that can be improved to help

save lives and reduce injuries in future hazard events.

5. Complete Task A on Worksheet #4.

Task B. Calculate the loss from each hazard event.

1. Calculate the losses to each asset.

To determine which individual assets could sustain the largest

potential losses, add the structure loss, content loss, and function

loss for each asset to determine the total loss. For example, you

expect your town library to be damaged by a 100-year flood and the

structural damage is estimated at $40,000. The content damage to

the books and other equipment is estimated at $22,500, and the loss

from having to close the library for a week and the displacement for

90 days is estimated at $45,908. By adding each loss, the total flood

loss for the library from a 100-year flood would be $108,408.

This information help you begin to form a picture of the damages

that could be sustained in a hazard. You now know how individual

hazard events can impact the various assists of your community or

state.

Losses to functions

= (functional downtime

costs) + (displacement time

costs)

Loss = structure loss +

content loss + function loss
4-6 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

2. Calculate the estimated damages for each hazard event.

To find out which hazard event could have the largest economic

losses for your community or state, total the loss from each hazard

event type. For example, if there are three buildings located in the

100-year floodplain with estimated total flood losses of $10,000,

$5,000, and $2,500, then your estimated flood loss from the 100-year

flood event is $17,500.

Next, to find out which hazard event would likely impact the

greatest proportion of the community or state, calculate the percent

of the value of the assets susceptible to damage from each hazard.

Divide the total hazard losses, by the total value of the assets you

assessed for that hazard (from Step 3). For example, if your flood

After you have calculated the losses, you may want to

assign a rank or relative priority to the losses to determine your mitigation

priorities. In fact, there have been numerous attempts by academicians,

communities, and states to develop quantitative methods to produce such

rankings, ranging from the very simple to the very complex, particularly

when losses were calculated using different probabilities of occurrence.

Experience has shown, however, that most communities do not rely on the relative

ranking of losses as the primary determinant of priorities in beginning to address

mitigation approaches. While quantitative processes form the basis of the risk determinations, political issues drive the decisions on which mitigation initiatives are

pursued first. In other words, decisions involving mitigation initiatives are usually

(and should be) discussed in the context of other ongoing planning processes that

include consideration of non-hazard-related community goals as well as those related to emergency management. This will be discussed further in the next phase of

the Natural Hazard Mitigation Planning Process.

Coastal hazard areas often present multiple risks at the same

time. For example, hurricanes may simultaneously create wind, inland

and coastal flooding, and erosion losses. Logically, the presence of multiple risks complicates the analysis process. Sometimes these risks do

not influence each other at all in the same hazard event and losses may

be analyzed separately and simply added up to get a picture of the total losses. At

other times risks may exacerbate or nullify each other. There is no single “best”

approach to assessing multiple risks. In general, it’s important first to understand

the losses created by individual hazards, then try to determine the interaction among

them.

It is perfectly legitimate from a statistical standpoint to add losses from different

hazards of the same frequency (and from different frequencies if the level of damage is normalized by probability calculations). For example, if a coastal house would

experience $14,000 damage in a 50-year wind event and $4,500 damage in a 50-

year flood, then the house has $18,500 combined 50-year losses.

It’s also true that one hazard can cancel another out at some point. For example,

let’s assume our coastal house would be destroyed by a 100-year wind event and

a 100-year flood would result in three feet of water in the same house. In this case,

the effect of flooding is negligible at the 100-year frequency since the house is

presumably already destroyed by the wind.

Combinations of risk are most often addressed by adjusting standard damage curves

to indicate the interactivity between or among risks.
estimate losses 4

Version 1.0 August 2001 4-7

losses are estimated at $17,500 and

the value of the three buildings

you assessed is $100,250, then your

flood losses would be approximately $17,500 divided by $100,250

or 17 percent of the value of the

assets.

3. Create a composite map.

Prepare a map that shows a composite of the areas of highest loss

(from Worksheet #4). You may

want to indicate areas affected by

multiple hazards as your high loss

potential areas and the areas with

one or no hazards as moderate or

low potential loss. Another alternative is to identify areas with

multiple critical facilities, major

employers, repetitively damaged

structures, and infrastructure as

high potential loss areas.

The state should compilelocal risk assessments

for a comprehensive summary and analysis of potential disaster losses.

This should combine the state’s risk assessment of state-owned structures as well as those from the local risk assessments. The information

provided from the local risk assessments should also be referenced in

the statewide mitigation plan.

For these reasons, you may consider specifying a general format for the information to be provided from the local communities as well as offering technical assistance to ensure the quality of the data. This might include help or training in

benefit-cost analysis and HAZUS, development expertise in interpreting damage

curves and estimating economic effects of lost functions for large-scale damages.

A composite loss

map can be created by

overlaying results of individual hazard maps to determine areas with

relatively more assets at

risk than others.

Although this process can

be enhanced by “weighting” the individual hazard

results, any method that

helps the community visualize areas with multiple

concerns can be helpful.

This process is best accomplished with GIS but

manual overlays with light

tables and tracing paper

will suffice.
4-8 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Summary

After this step you should have a good idea of which assets are

subject to the greatest potential damages and which hazard event is

likely to produce the greatest potential losses.

____

After you have estimated the expected losses from each of your

hazard events

Go to the afterword

 for information pertaining to the next step of the Natural Hazard

Mitigation Planning Process.

____
estimate losses 4

Version 1.0 August 2001 4-9

The Hazardville Post

Vol. CXI No. 319 Thursday, November 15, 2001

Town Council Alarmed by Risk Assessment Results

(Part 4 of a 4 part series on the Risk Assessment Process)

[Hazardville, EM] The members of the

Town Council were stunned last night

after learning the results of the risk assessment. At the public meeting to discuss the results, Joe Norris, lead planner of the Town of Hazardville Organization for Risk Reduction (THORR),

reported that Hazardville certainly deserves its name. Norris said that since

the last board meeting on December 4,

2001, THORR has computed the risk

from seven separate hazards (floods,

earthquakes, tsunamis, tornadoes,

coastal storms, landslides, and wildfires).

"After taking an inventory of all of

the assets in the community that lay

within the hazard zones, the team estimated the amount of damage the assets

would sustain based on the selected

magnitude of the hazard events," Norris

explained. "Using information we

gleaned from maps and tax assessment

records, we judged the possible structural damage, content damage, and consequences of the loss of function or

structure use, then calculated the likely

cost of this damage to the community."

As the Town Council members questioned Norris and the THORR

workgroup leaders, each disclosed the

dangers to which the town is subject.

Mr. David Waters, head of the Flood

and Coastal Storm Workgroup, testified

to the Council that the town's manufactured home park has the greatest vulnerability of flood hazards due to the low

elevation of the land in that area. "We

estimated that a 100-year storm event

would cause about two feet of flooding

inside many of the homes in the park,

which would result in about 63 percent

total damage," he reported. A 100-year

flood can also damage the bridge crossing the Raging River, especially if debris like timber and large rocks are

swept away by the running water. Waters stated that the coastal region is vulnerable to coastal storms, but the inland

areas can be flooded as well. "But the

biggest threat from coastal storms is the

erosion," stressed Waters. We estimated

that with the current rate of erosion at

five feet per year, the Hazardville boardwalk would be consumed by the Relentless Ocean within 60 years."

According to Ms. Wendy Soot, head

of the Tornadoes and Wildfires

Workgroup, erosion and flooding are not

the only threats to the manufactured

home park, the older areas of town, and

the boardwalk. She explained that these

areas are the most vulnerable assets to

tornadoes in town, however a tornado

could remove roofs, knock over walls,

and even overturn cars and trains in any

area of town. Soot, the town's Fire Marshal, added that a wildfire could spread

very quickly in the Tinderbox National

Forest and that a number of buildings in

that area are vulnerable to wildfires.
4-10 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

"The biggest initial concern for the

Workgroup, which was landslides, turned

out to be a very minor hazard in comparison," Tremble said. "A large landslide

could destroy the lighthouse on the

southwest shore of town and threaten the

only road out of town, but it does not

appear that landslides would cause the

widespread damage once imagined."

When asked what the cost of these

potential damages could be to the town,

Norris submitted to the Council a copy

of the team's composite loss map and

several hazard maps with a chart describing the criteria for determining the

levels of potential loss to the hazards

(see accompanying figures). The hazard maps exhibited the structures that

Norris explained that the team then

produced a Composite Loss Map (see

graphic opposite) by relating the potential losses across hazards. "The team noticed that much the shoreline faced moderate, high, and extreme vulnerability to

nearly every hazard. With so many different hazards presenting a high potential loss for this area, we decided that

their overall exposure to loss was 'extreme'. On the other hand, the Middle

Aged Residential Neighborhood has a

moderate vulnerability only to earthquakes; therefore, we decided that their

composite potential loss was 'moderate'." Norris cautioned that the loss values should not be compared across hazards because each has a different probability of occurrence, "however, the

composite loss map demonstrates which

areas of the community have the greatest potential of loss from the greatest

number of hazards."

When asked about the next steps for

the town in light of the risk assessment,

Norris replied, "Even though completing the risk assessment was challenging,

it will be the foundation for our hazard

mitigation plan. Now that we know what

is susceptible to the different hazards,

and what those hazards will do to the

buildings, infrastructure, and economy

of Hazardville, we can start answering

the question of how to deal with it."

the team considered to be at moderate,

high, and extreme potential for loss to

each hazard. For each structure, the team

determined the vulnerability thresholds

based on the vulnerability of structures

to the hazard and the probability of each

hazard occurring. "Our results show that

individually, each of these hazards shows

a significant risk to the town." The accompanying chart demonstrated the criteria by which team determined which

loss category the structures belonged.

"Because of the importance to the community during or after a disaster, a critical facility that exhibited potential vulnerability to the hazard we determined

should be in the 'high' or 'extreme' category."

Mary Tremble, director of the

Hazardville Emergency Management

Agency (HEMA) and head of the

THORR's Earthquake, Tsunami, and

Landslide Workgroup, testified that

Hazardville has a number of older

unreinforced masonry buildings that

are extremely vulnerable to earthquakes. In addition, earthquakes could

disrupt the power and water supply to

town by fracturing the lines or causing leaks. "Using HAZUS, we determined that an earthquake with 0.3g

could result in about $4 million in

damages." An offshore earthquake

that produces a tsunami could also

result in major damage to the coastal

areas and moderate damage to the

Town's police and fire department.
estimate losses 4

Version 1.0 August 2001 4-11

Significant Portions of the

Hazardville Community are

at “High” or “Extreme”

Vulnerability to Hazards

Hazardville Loss Estimation Criteria

Hazard Type

Moderate Criteria

(Yellow) High Criteria (Orange) Extreme Criteria (Red)

Floods

• Structures prone to less

than 1 foot flooding

• Structures prone to 1 to 4 feet

flooding

• Mobile homes in floodplain

• Critical facilities in floodplain

• Structures in floodway, or prone to >4 feet

flooding or velocities >3 feet per second

• Critical facilities prone to >2 feet flooding or

velocities >3 feet per second

• Mobile homes prone to >2 feet flooding or

velocities >3 feet per second

• Repetitive flood loss structures

Earthquakes • s Wood-frame structures • Pre-seismic code structure

• Unreinforced masonry buildings

• Structures on or near soils prone to liquefaction

• Critical facilities built pre-seismic code

Tsunamis

• t Structures near the coast • Critical facilities near the coas

• Pre-seismic or pre-flood code

structures near the coast

• Pre-seismic or pre-flood code structures

adjacent to the shoreline

Tornadoes

• s Pre-wind code structures • Historic building

• Critical facilities

• Mobile homes

• Pre-wind code critical facilities

• Overhead power lines

Coastal

Storms

• Structures near the

shoreline

• Structures in the 100-

year floodplain

• Pre-flood or pre-wind code

structures near the shoreline

(including A or X zones)

• Critical facilities near the shoreline (including A or X zones)

• Structures located in coastal V zones, seaward

of dunes, or in areas with high erosion rates

• Pre-flood or pre-wind code critical facilities

Landslides

• Structures near steep

slopes

• Structures near steep slopes

prone to erosion

• Structures near steep slopes that have soils

prone to liquefaction

• Structures near previous landslide areas

Wildfires

• Structures in close

proximity to areas with

light or medium fuels with

slopes less than 40%

• Structures in close proximity

to areas with medium fuels

with slopes 41-60%

• Critical facilities in close proximity to areas with

medium fuels and slopes 41 percent+

• Other structures in close proximity to areas with

medium fuels and slopes 61 percent+

• Other structures in close proximity to areas with

heavy fuels and slopes 41 percent+
4-12 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Floods

Task A. Determine the extent of damages from floods.

These loss estimation tables provide only very broad estimates based

on historical trends. To get a better idea of the likely damage

associated with a given flood level, you should conduct further

research on the structure by talking with a structural engineer.

1. Calculate losses to structures due to floods.

In assessing physical vulnerability, the most important factor is the

extent to which structures get damaged when they are exposed to

water, high velocity, and debris impact. As compared to some of the

other hazards considered in this guide, the effect of floods on

building performance is fairly well understood and documented.

The Flood Building Loss Estimation Table at right depicts the

extent of damage from various flood depths on different kinds of

structures. This table is from the FEMA Benefit-Cost Analysis Module and has been compiled based on flood damage across the

country. This table provides a rule of thumb and may need to be

adjusted for extenuating circumstances. There are many sources of

this kind of information, often called “damage curves.” The library

(Appendix B) provides several references.

Depth of Flooding. Using the information you gathered previously,

estimate the base flood depth at the location you are assessing by

subtracting the lowest floor elevation from the base flood elevation.

Flood vulnerability is

the likelihood of something to

be damaged in a flood. Generally, it is measured by how

much something will be damaged as a percentage of its replacement

value. For example, the Federal Insurance Administration database shows that

a particular kind of house will get 35 percent damage if 4 feet of water inundated

it. Another building gets 20 percent damage at the same flood depth. The building that gets the 35 percent damage is

more vulnerable to flood damage. Remember that this is only one of the components of risk. Later in this section, you’ll

learn how to use this information to determine the expected future damages

from one or more floods.

There are two things that determine vulnerability to a flood. The first is the tendency of physical things to get damaged.

The second is the potential loss of function from losing certain elements of a

community because of a flood. These are

combined in the discussion at right, although they must be separately counted.

Floods

In this example, the first floor elevation is 5 feet above mean sea level;

therefore, this structure would experience approximately 7 feet of flooding in

a 100-year flood event.
Version 1.0 August 2001 4-13

estimate losses 4

Percent Structural Damage.

Using the Flood Building Loss

Estimation Table at right, find

the type of structure you’re

assessing, match it with the

estimated flood depth and

determine the percent damage

expected to that particular

building.

For example, a two-story residential building without a

basement that had 7 feet of

flooding is estimated to result in

26 percent structural damage.

But a manufactured home with

7 feet of flooding would result

in 82 percent structural damage.

2. Calculate losses to contents due

to floods.

The Flood Contents Loss

Estimation Table shown here

provides a simplified indication

of the percent damage to

building contents for various

depths of flooding.

Percent Contents Damage.

Using the depth of flooding

determined above, find the type

of building you’re assessing on

the Flood Contents Loss Estimation Table, match it with the

estimated depth of flooding for

that area of your community,

and determine the percent

contents damage. For example,

a two-story residential building

without a basement that had 7

feet of flooding is estimated to

result in 39 percent contents

damage, whereas a manufacFlood Contents Loss Estimation Table

Flood

Depth

(feet)

One Story

No Basement

(% Contents

Damage)

Two Story

No Basement

(% Contents

damage)

One or Two

Story With

Basement

(% Contents

damage)

Manufactured

Home

(% Contents

damage)

-2 0 0 6 0

-1 0 0 12 0

0 13.5 7.5 16.5 12

1 21 13.5 22.5 66

2 33 19.5 30 90

3 40.5 27 34.5 90

4 43.5 30 42 90

5 45 33 49.5 90

6 60 36 57 90

7 64.5 39 66 90

8 66 43.5 73.5 90

>8 67.5 49.5 76.5 90

Source: FEMA Benefit-Cost Analysis Full Data Module 3/10/99

It is important to note that this table is based on data from a wide range

of building uses, including public/nonprofit, commercial, residential, and mixed

buildings. It can also be used to evaluate infrastructure projects.

Flood Building Loss Estimation Table

Flood

Depth

(feet)

One Story

No Basement

(% Building

Damage)

Two Story

No Basement

(% Building

damage)

One or Two

Story With

Basement

(% Building

damage)

Manufactured

Home

(% Building

damage)

-2 0 0 4 0

-1 0 0 8 0

0 9 5 11 8

1 14 9 15 44

2 22 13 20 63

3 27 18 23 73

4 29 20 28 78

5 30 22 33 80

6 40 24 38 81

7 43 26 44 82

8 44 29 49 82

>8 45 33 51 82

Source: FEMA Benefit-Cost Analysis Full Data Module 3/10/99
4-14 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

tured home with 7 feet of flooding would result in 90 percent

contents damage.

Since the contents damage chart has been established over many

flood events, the values are for generic contents. If you know that a

particular building would endure an extraordinary amount of

contents damage due to the particular contents, you should increase

this value. For example, you should increase the amount of contents

damage if a residence located in the floodplain contained valuable

antiques or if you know an area is prone to excessively muddy water

or contamination.

3. Calculate losses to building use and function due to floods.

The tables shown below and at right provide a simplified indication

of functional downtime and displacement time for buildings due to

various depths of flooding.

Functional Downtime. Using the

depth of flooding determined

previously, find the type of building you’re assessing on the Flood

Functional Downtime Table,

match it with the estimated depth

of flooding for that area of your

community, and determine the

functional downtime.

For example, a business in a twostory building without a basement

that had 7 feet of flooding would

be closed for approximately 26

days before business can resume in

another location. By contrast, a

business in a manufactured home

with 7 feet of flooding would be

closed for 30 days before resuming

business in another location.

Displacement Time. Using the depth of flooding determined above,

find the type of building you’re assessing on the Flood Displacement

Time Table, match it with the estimated depth of flooding for that

area of your community, and determine the displacement time.

For example, a business located in a two-story building without a

basement that had 7 feet of flooding would be displaced from its

regular building for approximately 158 days, while a business loV Zone Flood Functional Downtime Table

Flood depth Building without obstructions Building with obstructions

(feet) (functional downtime in days)

-0 0 8

-0 0 7

-0 0 6

-0 0 5

-0 0 4

-0 0 3

- 0 2 1 02

- 2 1 1 22

0 51 42

1 32 92

2 03 03

3 03 03

4 03 03

5 03 03

6 03 03

7 03 03

8 03 03

> 6 8 3 03

Source: FEMA Benefit-Cost Analysis Coastal V Zone Module 2/28/99

States should remember to include the contents

from state owned facilities

that are located in the floodplain, including vehicles and

equipment.
Version 1.0 August 2001 4-15

estimate losses 4

cated in a manufactured home

with 7 feet of flooding would be

displaced for 365 days.

4. Consider human losses due to floods.

In the event that an area is subject

to flash flooding where there are

insufficient warning systems, it is

possible that in basements or lower

areas of homes, deaths can occur,

especially if flash flooding occurs

overnight. This situation (flash

flooding) can also add to the

contents damage of some buildings

if there is not enough time to

move contents to upper floors.

Storm surge, tsunamis,

and flash floods can result in

casualties, but deaths or injuries from non-flash riverine

floods are relatively uncommon and are not considered in the guide.

V Zone Flood Displacement Time Table

Flood depth Building without obstructions Building with obstructions

(feet) (displacement time in days)

-0 0 8

-0 0 7

-0 0 6

-0 0 5

-0 0 4

-0 0 3

- 0 2 3 0 11

- 6 1 4 2 12

0 07 2 14

1 4 1 2 3 18

2 0 2 6 3 24

3 5 3 5 6 36

4 5 3 5 6 36

5 5 3 5 6 36

6 5 3 5 6 36

7 5 3 5 6 36

8 5 3 5 6 36

> 5 8 3 5 6 36

Source: FEMA Benefit-Cost Analysis Coastal V Zone Module 2/28/99

____

Go to the next hazard on your list to

estimate losses

or if you are finished with all your assessments

Go to the afterword

____
4-16 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

The quickest and easiest method of calculating risk

from an earthquake is

through the use of HAZUS.

You will need to select a scenario earthquake or to base your analysis on a historic event; otherwise, all of

the calculations and mapping will be completed for you.

Task A. Determine the extent of damages from earthquakes.

There are a number of factors that determine a building’s performance in an earthquake. Mostly these have to do with the structural

system, but things like height, the design of the first story, and

building materials are also factors. In assessing the physical vulnerability of structures, the most important factor is how fragile they

are. Fragility is the tendency of something to deform or break when

it is subjected to stress. The more fragile something is, the more

vulnerable it is. For example, most communities have some buildings that are constructed of unreinforced masonry. These buildings

are often made of brick or stone and lack steel reinforcing to resist

the effects of earthquakes.

When the earth is still, most of the forces on the walls of a masonry

building are compressive, but in an earthquake, tension is introduced into structures from side-to-side movements such as swaying.

Brick and stone are good at resisting compression or crushing, but

are poor in resisting the effects of tension, which occurs when a

building is being pulled apart. Unreinforced masonry buildings have

little resistance to this kind of force, and often collapse under

relatively light ground shaking.

1. Calculate losses to structures due to earthquakes.

The tables on the following pages provide a simplified indication of

the damages to different kinds of buildings at various PGA values.

For each building in your inventory, find the type of building you

are assessing on the correct table and match the PGA value with the

seismic design level (discussed in Step 3) to determine the estimated

percent structural damage.

For example, if you are assessing a wood-framed single-family home

constructed to high seismic building codes, in a 0.5 g PGA zone, you

would estimate the structure to sustain 10 percent damage in an

earthquake. However, the same structure built prior to any seismic

building codes would sustain 32 percent structural damage.

2. Calculate the losses to contents due to earthquakes.

Building contents are often vulnerable to damage during an earthquake. Your risk assessment should estimate the likely value of

contents within buildings that are similar, such as residences. You

Vulnerability of Contents

Building contents are also vulnerable to

damage during an earthquake. Contents

are most often damaged by falling, so an

assessment will gauge not only if contents will fall under certain shaking conditions, but also whether they will break if

they do fall. Remember, a full-blown risk

assessment might include visits to many

unique buildings in community, but for ordinary buildings such as residences, the vulnerability of

contents will be quite similar

from place to place.

Earthquakes

(continued on page 4-23)
Version 1.0 August 2001 4-17

estimate losses 4

Earthquake Single Family Residence Loss Estimation Tables

PGA

(g)

Building Damage Ratio (%)**

Wood Frame Construction Reinforced Masonry Unreinforced

Masonry

High* Moderate* Low* Precode* High* Moderate* Low* Precode* Low* Precode*

0 6 .55 1 1 1. 1 6 6. 3 8 0. 3 5 6. 1 7 1. 2 9 7. 4 1 3. 5 0 3. 4 6 5. 55.

0 2 .50 1 0 0. 1 0 4. 2 7 6. 3 6 1. 9 8 . 2 6 2. 3 1 6. 4 5 6. 3 8 8. 46.

0 7 .45 8 6 . 1 1 1. 2 1 1. 2 3 7. 8 7 . 1 7 9. 3 8 1. 4 0 0. 3 2 4. 41.

0 1 .40 6 6 . 7 1 . 1 7 3. 1 1 6. 6 1 . 1 6 2. 1 1 8. 2 8 5. 2 1 2. 28.

0 4 .35 4 3 . 6 1 . 1 8 0. 1 9 2. 4 8 . 8 2 . 1 8 5. 2 9 0. 1 8 8. 23.

0 9 .30 2 9 . 3 2 . 7 4 . 9 5 . 3 1 . 6 4 . 1 3 1. 1 4 6. 1 7 5. 19.

0 3 .25 2 2 . 3 6 . 4 1 . 6 4 . 2 9 . 3 7 . 8 4 . 1 2 2. 1 9 0. 14.

0 3 .20 1 7 . 1 8 . 2 3 . 3 3 . 1 5 . 2 1 . 6 0 . 9 5 . 6 4 . 9.

0 7 .15 0 0 . 1 3 . 1 8 . 1 4 . 0 5 . 1 4 . 2 1 . 4 0 . 3 3 . 4.

0 3 .10 0 4 . 0 6 . 0 7 . 0 3 . 0 5 . 0 8 . 0 1 . 1 3 . 1 0 . 2.

0 1 .07 0 2 . 0 3 . 0 4 . 0 1 . 0 2 . 0 4 . 0 5 . 0 6 . 0 0 . 1.

0 0 .05 0 0 . 0 1 . 0 1 . 0 0 . 0 1 . 0 1 . 0 2 . 0 2 . 0 5 . 0.

0 0 .03 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 1 . 0 1 . 0 2 . 0.

PGA

(g)

Loss of Function (# of Days)

Wood Frame Construction Reinforced Masonry Unreinforced

Masonry

High* Moderate* Low* Precode* High* Moderate* Low* Precode* Low* Precode*

0 0 .55 4 97 5 1 3 9 2 1 8 6 6 2 0 4 4 2 3 5 9 4 4 9 5 54

0 1 .50 3 96 9 1 1 5 2 1 4 5 8 1 5 9 3 4 6 4 9 8 3 0 9 50

0 3 .45 2 15 9 1 1 1 2 4 0 4 9 1 8 6 3 9 1 4 6 3 3 7 5 45

0 4 .40 1 72 86 1 1 4 1 2 59 4 1 6 8 2 8 7 2 6 3 32

09 3 .35 2 74 08 81 76 3 1 6 5 2 1 3 2 1 0 28

04 0 .30 1 03 55 41 64 7 1 9 1 1 1 8 1 9 6 23

03 8 7 .25 1 439 62 19 0 1 4 5 1 5 0 18

02 3 9 5 .20 14 61 85 6 1 4 0 6 4 11

012 3818 4 .15 2 15 62 94

00 1 13 1 2 7 4 .10 1 01 72

00 0 110 1 27 6 2 .07 1

00 0 0 10 0 11 1 7 .05

00 0 000 0 01 1 1 .03

* High, Moderate, Low and Precode refer to the general seismic design level

**Building Damage Ratio = Repair Cost / Replacement Value

Source: HAZUS
4-18 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Earthquake Apartment Building Loss Estimation Tables

PGA

(g)

Building Damage Ratio (%)**

Wood Frame Construction Reinforced Masonry Unreinforced

Masonry

High* Moderate* Low* Precode* High* Moderate* Low* Precode* Low* Precode*

0 7 .55 1 0 1. 1 5 5. 2 2 5. 3 2 0. 1 5 2. 2 4 4. 3 4 6. 4 9 3. 3 7 7. 43.

0 2 .50 1 2 0. 1 2 3. 2 5 2. 2 2 6. 1 4 0. 2 3 0. 3 7 0. 3 6 7. 3 4 2. 38.

0 9 .45 8 1 . 1 6 1. 1 0 8. 2 9 2. 8 8 . 1 4 7. 2 1 6. 3 8 3. 2 1 8. 34.

0 6 .40 6 1 . 8 5 . 1 6 2. 1 9 2. 6 4 . 1 1 1. 1 9 6. 2 8 0. 1 7 9. 23.

0 8 .35 4 7 . 6 7 . 9 0 . 1 5 0. 5 6 . 8 1 . 1 3 3. 1 4 7. 1 0 6. 20.

0 3 .30 3 2 . 4 3 . 7 6 . 7 0 . 4 0 . 6 9 . 9 4 . 1 5 3. 1 5 3. 16.

0 5 .25 2 5 . 3 9 . 4 1 . 5 7 . 2 0 . 4 6 . 7 2 . 1 1 0. 9 6 . 12.

0 5 .20 1 9 . 1 0 . 3 2 . 3 5 . 1 6 . 2 4 . 5 9 . 6 5 . 5 5 . 7.

0 7 .15 0 1 . 1 5 . 1 6 . 1 5 . 0 6 . 1 3 . 2 4 . 3 9 . 2 5 . 3.

0 3 .10 0 4 . 0 5 . 0 6 . 0 3 . 0 5 . 0 8 . 0 0 . 1 2 . 1 7 . 1.

0 1 .07 0 2 . 0 3 . 0 3 . 0 1 . 0 2 . 0 4 . 0 5 . 0 6 . 0 8 . 0.

0 0 .05 0 0 . 0 1 . 0 1 . 0 0 . 0 1 . 0 1 . 0 2 . 0 2 . 0 3 . 0.

0 0 .03 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 1 . 0 1 . 0.

PGA

(g)

Loss of Function (# of Days)

Wood Frame Construction Reinforced Masonry Unreinforced

Masonry

High* Moderate* Low* Precode* High* Moderate* Low* Precode* Low* Precode*

0 5 .55 4 18 5 2 4 0 3 4 1 7 1 3 5 2 5 0 0 7 8 2 6 0 0 73

0 5 .50 3 27 9 1 2 6 2 1 7 6 7 2 6 5 4 2 2 6 7 4 5 3 2 66

0 5 .45 2 75 0 1 8 3 2 3 1 5 9 2 9 1 3 2 6 5 0 8 4 6 7 60

0 4 .40 1 03 57 5 1 8 2 2 1 1 5 2 2 3 1 3 2 6 3 5 1 40

0 0 .35 1 62 15 29 12 48 7 1 9 7 3 2 0 2 1 6 35

04 0 .30 1 33 36 61 75 5 1 7 3 2 9 4 2 8 0 29

03 9 9 .25 1 93 01 13 4 1 5 0 1 3 9 1 0 3 23

02 3 0 .20 1 614 91 27 9 1 6 2 7 7 14

012 3919 8 .15 2 95 23 56

0 0 1 13 1 2 8 6 .10 1 21 23

0 0 0 110 1 28 7 3 .07 1

0 0 0 0 10 0 11 17 .05

00 0 000 0 000 1 .03

* High, Moderate, Low and Precode refer to the general seismic design level

**Building Damage Ratio = Repair Cost / Replacement Value

Source: HAZUS
Version 1.0 August 2001 4-19

estimate losses 4

Earthquake Professional Office Building Loss Estimation Tables

PGA

(g)

Building Damage Ratio (%)**

Concrete Wall Construction Steel Frame (Braced)

High* Moderate* Low* Precode* High* Moderate* Low* Precode*

0 0 .55 1 7 4. 2 0 3. 3 7 7. 4 5 3. 1 6 4. 1 2 8. 3 3 1. 38.

0 0 .50 1 0 2. 2 0 0. 3 1 1. 3 1 9. 1 2 2. 1 0 5. 2 1 5. 32.

0 9 .45 9 2 . 1 2 7. 2 2 7. 3 5 4. 1 3 0. 1 8 3. 2 6 0. 27.

0 2 .40 7 4 . 1 5 1. 1 0 6. 2 9 2. 7 1 . 9 1 . 1 5 3. 17.

0 4 .35 5 4 . 9 5 . 1 4 3. 1 5 8. 6 3 . 7 0 . 1 6 0. 13.

0 2 .30 4 2 . 7 0 . 1 2 0. 1 7 4. 4 4 . 5 5 . 7 1 . 10.

0 0 .25 3 7 . 4 8 . 7 0 . 1 7 1. 3 0 . 4 3 . 5 4 . 7.

0 0 .20 2 9 . 2 6 . 5 1 . 8 5 . 2 9 . 2 7 . 3 2 . 5.

0 0 .15 1 8 . 1 2 . 3 4 . 5 5 . 1 7 . 1 4 . 2 2 . 3.

0 4 .10 0 6 . 0 0 . 1 5 . 1 5 . 0 7 . 0 9 . 0 3 . 1.

0 2 .07 0 3 . 0 4 . 0 6 . 0 2 . 0 3 . 0 4 . 0 5 . 0.

0 0 .05 0 1 . 0 2 . 0 2 . 0 0 . 0 1 . 0 2 . 0 2 . 0.

0 0 .03 0 0 . 0 0 . 0 1 . 0 0 . 0 0 . 0 0 . 0 0 . 0.

PGA

(g)

Loss of Function (# of Days)

PreCast Concrete Tilt-up Light Metal Building

High* Moderate* Low* Precode* High* Moderate* Low* Precode*

0 4 .55 1 44 78 0 1 6 1 1 23 37 99

0 2 .50 1 53 37 99 31 62 75 58

09 0 .45 3 46 98 01 22 74 47

05 7 .40 1 53 55721 52 34

04 4 .35 1 92 64 59 81 33

03 0 .30 1 12 63 37 31 52

02 6 6 .25 1 82 348 71

01 3 1 .20 1 12 235 11

01 2 6 4 .15 1 1137

00 0 1 3 0 0 1 2 .10

00 0 0 1 0 0 0 1 .07

00 0 0 0 0 0 0 0 .05

00 0 0 0 0 0 0 0 .03

* High, Moderate, Low and Precode refer to the general seismic design level

**Building Damage Ratio = Repair Cost / Replacement Value

Source: HAZUS
4-20 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

E s arthquake Retail Trade Building Loss Estimation Table

PGA

(g)

Building Damage Ratio (%)**

Steel Frame (Braced) Reinforced Masonry Unreinforced

Masonry

High* Moderate* Low* Precode* High* Moderate* Low* Precode* Low* Precode*

0 2 .55 1 0 4. 1 3 9. 3 6 3. 4 9 1. 1 0 1. 2 7 5. 3 4 7. 4 0 5. 4 2 0. 46.

0 8 .50 1 5 1. 1 7 5. 2 0 6. 3 0 5. 1 9 0. 2 6 0. 3 9 1. 3 8 9. 3 3 4. 41.

0 1 .45 1 5 0. 1 1 3. 2 2 2. 3 8 0. 8 2 . 1 7 8. 2 4 7. 3 9 5. 3 1 0. 37.

0 5 .40 7 1 . 9 6 . 1 0 3. 1 7 9. 6 6 . 1 0 1. 1 8 7. 2 5 2. 2 4 1. 26.

0 1 .35 6 2 . 7 4 . 1 8 0. 1 3 4. 5 7 . 8 0 . 1 1 4. 1 9 9. 1 5 7. 22.

0 4 .30 4 4 . 5 7 . 7 0 . 1 9 1. 3 1 . 6 6 . 1 0 0. 1 7 5. 1 9 4. 18.

0 5 .25 3 9 . 3 4 . 5 0 . 8 6 . 2 1 . 4 3 . 8 7 . 1 9 1. 9 5 . 14.

0 4 .20 2 8 . 2 8 . 3 6 . 5 5 . 1 7 . 2 9 . 5 3 . 8 1 . 6 7 . 8.

0 4 .15 1 6 . 1 4 . 2 5 . 3 5 . 0 5 . 1 6 . 2 2 . 4 1 . 3 3 . 4.

0 5 .10 0 6 . 0 9 . 0 4 . 1 3 . 0 5 . 0 9 . 0 2 . 1 3 . 1 1 . 2.

0 2 .07 0 3 . 0 4 . 0 5 . 0 1 . 0 2 . 0 4 . 0 6 . 0 7 . 0 0 . 1.

0 0 .05 0 1 . 0 2 . 0 2 . 0 0 . 0 1 . 0 1 . 0 2 . 0 2 . 0 5 . 0.

0 0 .03 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 0 . 0 1 . 0 1 . 0 1 . 0.

PGA

(g)

Loss of Function (# of Days)

Steel Frame (Braced) Reinforced Masonry Unreinforced

Masonry

High* Moderate* Low* Precode* High* Moderate* Low* Precode* Low* Precode*

0 7 .55 1 43 67 2 1 2 0 1 15 88 0 1 4 1 9 5 11

0 4 .50 1 82 16 88 01 14 67 99 28 4 10

0 1 .45 1 32 94 779 63 66 09 37 39

07 3 .40 1 72 545 02 83 75 94 76

05 0 .35 1 91 534 41 23 94 14 85

03 8 4 .30 1 6239 52 93 33 94

02 4 9 8 .25 125 91 13 12 83

02 3 6 2 .20 1 13 21 22 41 42

01 1370 2 5 0 .15 1621

00 0 120 0 13 2 6 .10

00 0 000 0 0112 .07

00 0 000 0 000 1 .05

00 0 000 0 0000 .03

* High, Moderate, Low and Precode refer to the general seismic design level

**Building Damage Ratio = Repair Cost / Replacement Value

Source: HAZUS
Version 1.0 August 2001 4-21

estimate losses 4

Earthquake Wholesale Trade Warehouse Loss Estimation Tables

PGA

(g)

Building Damage Ratio (%)**

PreCast Concrete Tilt-up Light Metal Building

High* Moderate* Low* Precode* High* Moderate* Low* Precode*

0 9 .55 1 8 5. 2 9 6. 3 8 2. 3 5 5. 2 8 5. 3 3 3. 5 0 0. 56.

0 1 .50 1 5 4. 2 6 3. 2 0 9. 3 8 3. 2 1 1. 2 5 9. 4 7 4. 51.

0 2 .45 1 1 2. 2 5 1. 2 0 6. 3 2 0. 1 5 8. 2 0 5. 4 7 0. 47.

0 4 .40 9 8 . 1 9 4. 1 1 8. 2 5 2. 1 9 2. 1 3 6. 2 6 6. 32.

0 9 .35 7 8 . 1 2 1. 1 4 6. 1 8 9. 9 2 . 1 9 4. 2 3 1. 28.

0 8 .30 5 5 . 8 5 . 1 4 3. 1 4 6. 7 4 . 1 5 1. 1 3 7. 23.

0 2 .25 4 1 . 6 9 . 1 7 0. 1 6 3. 5 1 . 9 6 . 1 0 3. 19.

0 6 .20 2 1 . 4 3 . 8 8 . 1 8 0. 3 4 . 5 3 . 1 8 0. 14.

0 5 .15 1 2 . 2 3 . 4 7 . 6 1 . 2 1 . 3 1 . 7 4 . 10.

0 6 .10 0 0 . 1 7 . 1 4 . 2 9 . 0 4 . 1 7 . 2 2 . 5.

0 2 .07 0 4 . 0 5 . 0 6 . 0 4 . 0 7 . 0 0 . 1 6 . 1.

0 1 .05 0 1 . 0 2 . 0 5 . 0 1 . 0 2 . 0 3 . 0 6 . 0.

0 0 .03 0 0 . 0 1 . 0 1 . 0 0 . 0 1 . 0 1 . 0 2 . 0.

PGA

(g)

Loss of Function (# of Days)

PreCast Concrete Tilt-up Light Metal Building

High* Moderate* Low* Precode* High* Moderate* Low* Precode*

0 7 .55 2 96 2 1 0 0 1 2 2 5 87 7 1 2 1 13

0 3 .50 2 06 09 1 1 4 1 4 86 7 1 5 0 12

0 0 .45 2 45 18 3 1 7 0 3 06 79 8 11

0 4 .40 1 53 35 27 42 04 56 38

0 1 .35 1 62 54 36 81 43 65 57

08 8 .30 1 73 45 41 82 54 46

05 2 .25 1 03 54 01 22 63 45

04 8 2 .20 2 63631 82 34

02 4 1 .15 1 12 47 02 23

01 2 4 7 2 3 8 7 .10 1

00 1 1 2 1 2 3 6 .07

00 0 0 1 0 0 1 2 .05

00 0 0 0 0 0 0 0 .03

* High, Moderate, Low and Precode refer to the general seismic design level

**Building Damage Ratio = Repair Cost / Replacement Value

Source: HAZUS
4-22 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Earthquake Light Industrial Facility Loss Estimation Tables

PGA

(g)

Building Damage Ratio (%)**

PreCast Concrete Construction

High* Moderate* Low* Precode*

0 7 .55 1 4 5. 2 0 1. 2 9 4. 25.

0 1 .50 1 9 4. 1 6 8. 2 7 1. 23.

0 3 .45 1 9 2. 1 9 6. 1 0 8. 21.

0 0 .40 1 4 0. 1 4 2. 1 3 4. 16.

0 5 .35 8 3 . 1 4 0. 1 2 2. 14.

0 1 .30 6 7 . 7 1 . 1 8 0. 11.

0 3 .25 4 5 . 5 0 . 8 6 . 9.

0 6 .20 2 9 . 3 0 . 6 4 . 7.

0 5 .15 1 1 . 2 3 . 3 7 . 4.

0 5 .10 0 8 . 0 4 . 1 8 . 1.

0 1 .07 0 4 . 0 4 . 0 5 . 0.

0 1 .05 0 1 . 0 2 . 0 3 . 0.

0 0 .03 0 0 . 0 1 . 0 1 . 0.

PGA

(g)

Loss of Function (# of Days)

PreCast Concrete Tilt-up

High* Moderate* Low* Precode*

0 6 .55 2 56 99 8 11

0 2 .50 2 65 78 9 10

0 9 .45 1 15 87 1 10

0 3 .40 1 33 15 96

0 1 .35 1 52 34 06

07 7 .30 1 53 15

05 1 .25 1 82 34

04 7 1 .20 2 43

02 3 0 .15 1 91

01 2 4 6 .10

00 1 1 2 .07

00 0 0 2 .05

00 0 0 0 .03

* High, Moderate, Low, and Precode refer to the general seismic design level

**Building Damage Ratio = Repair Cost / Replacement Value

Source: HAZUS
Version 1.0 August 2001 4-23

estimate losses 4

might also want to conduct site visits of buildings with unique or

especially valuable community assets.

Contents loss estimation tables are not currently available for

earthquake damage. Your estimated contents loss should be based

on the replacement value of the contents, the potential of the

contents to break or fall and the estimated percent structural

damage. As a rule, the percent contents damage will usually be one

half of the percent structural damage.

For example, if you were assessing a residential building with an

estimated 40 percent building damage, you would estimate that the

contents damage would be 20 percent of the building’s replacement

value.

3. Calculate the losses to building use and function due to earthquakes.

In this step you will assess community or state vulnerability in terms

of loss of function. In this area, vulnerability is directly related to

how long a function will be interrupted due to an earthquake. You

will estimate how long particular functions in the community will be

interrupted because of an earthquake.

Building loss of function times (in days) are presented in the tables

on the preceding pages. These times represent estimates of the

average time for actual cleanup and repair, or reconstruction. These

estimates should be extended to account for delays in decisionmaking, financing, inspection etc., as necessary. For each building

in your inventory, find the type of structure you are assessing on the

correct table and match the PGA value with the seismic design level

to determine the estimated loss of function (in days).

For example, if you were assessing a wood-framed single-family

home constructed to high seismic building codes, subject to 0.5 g

PGA, you would estimate 31 days of lost function. However the same

structure built prior to any seismic building codes would sustain 241

days of lost function.

Estimating the contents losses due to earthquakes can be a difficult process and in many cases may be counter

intuitive to non-technical users. For example, buildings designed under

high seismic building codes may actually have a higher proportion of

content damage than older/weaker buildings, because they are designed

to sway and absorb the motion of the ground movements.

Earthquake contents damage ratios are generally around half of the building’s damage ratios. This relative proportion is slightly higher for structures built using higher

seismic design codes and decreases for buildings constructed under low seismic

design codes, although these differences are not major. HAZUS will give you more

accurate estimates of potential contents damage from earthquakes.

For earthquakehazards, HAZUS provides users with estimates of:

 Physical damage to buildings and critical facilities;

 Direct and indirect economic losses;

 Repair and replacement

losses; and

 Social impacts.

(continued from page 4-16)
4-24 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

4. Calculate human losses due to earthquakes.

While direct deaths and injuries from an earthquake are unlikely,

they can occur as an indirect result when structures collapse. Evaluate your current and previous seismic building codes to determine

the number of people living in buildings constructed before the

seismic building code was adopted, or in buildings located in densely

populated areas.

____

Go to the next hazard on your list to

estimate losses

or if you are finished with all your assessments

Go to the afterword

____
Version 1.0 August 2001 4-25

estimate losses 4

Task A. Determine the extent of damage from tsunamis.

In assessing physical vulnerability, the most important factor is the

extent to which structures get damaged when they are exposed to

tsunamis. Structures located in coastal areas with known offshore

faults are at the greatest risk of damage from tsunamis.

1. Calculate losses to structures due to tsunamis.

Since there are not any standard loss estimation models and tables

for tsunamis, your estimated structure vulnerability will be based on

the proximity of the structure to the shoreline, and/or past occurrences of tsunamis.

If you hired a geologist or other expert to create your community’s

tsunami hazard map, he or she may also be able to estimate the

potential damage for you.

2. Calculate losses to contents due to tsunamis.

Again, there are not any standard loss estimation models and tables

for contents damage from tsunamis. Your estimated contents loss

should be based on the structural damage you just determined.

3. Calculate losses to structure use and function due to tsunamis.

Vulnerability is directly related to how long a function will be

interrupted due to a tsunami. Since there are not any standard

displacement time or functional downtime tables for tsunamis, such

as there are for floods, you must estimate how long particular

functions will be interrupted because of a tsunami hazard event. Go

to page 4-4, “Estimate the losses to structure use and function” to

find specific advice on how to assess the displacement time and

functional downtime.

4. Calculate human losses due to tsunamis.

In the event that an area is subject to tsunamis, it is possible that

deaths can occur. You may need to rely on statistics from past

tsunamis in your area to determine the vulnerability of the population to tsunamis.

The state should focus on areas where tsunamis may inundate major

transportation routes, and

state-owned facilities, or impact facilities that would have statewide

effects, such as airports, ports, and critical facilities that serve large areas.

As a rule of thumb,

use the vulnerability assumptions and figures that you will

use for the flood component

of coastal storms and increase them if necessary.

Tsunamis
4-26 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

____

Go to the next hazard on your list to

estimate losses

or if you are finished with all your assessments,

Go to the afterword

____
Version 1.0 August 2001 4-27

estimate losses 4

Task A. Determine the extent of damage from tornadoes.

In assessing vulnerability, the most important factor is how likely

structures are to fail when they are subjected to wind loads that

exceed their design or to flying debris that penetrates the building.

Structural damages from tornadoes are a function of the building’s

location relative to the tornado vortex, which cannot be predicted

or mapped. In general, building damages can range from cosmetic

to complete structural failure, depending on wind speed and location of the building with respect to the tornado path. Only a

qualified architect or structural engineer can do more than the

most rudimentary analysis of a building’s capacity to resist the

effects of tornadoes.

1. Calculate losses to structures due to tornadoes.

Since there are not any standard loss estimation models and tables

for tornadoes, your estimated structure vulnerability will be based

on past occurrences of tornadoes and the design wind speed you

determined in Step 2.

2. Calculate losses to contents due to tornadoes.

Again, there are not any standard loss estimation models and tables

for content damage from tornadoes. Your estimated content losses

should be based on the amount of damage to the structures.

3. Calculate losses to structure use and function due to tornadoes.

Vulnerability is directly related to how long a function will be

interrupted due to a tornado. Since there are not any standard

displacement time or functional downtime tables for tornadoes, you

will estimate how long particular functions will be interrupted

because of a tornado hazard event. Go to page 4-4, “Estimate the

losses to structure use and function“ to find specific advice on how

to assess the displacement time and functional downtime.

4. Calculate human losses due to tornadoes.

The safest place for people during a tornado is in a safe-room or

storm shelter designed to specific performance criteria. Communities should assess the number, location, capacity, and strength of

shelters throughout the community to ensure they are able to house

residents and withstand the design wind speed. This is primarily the

responsibility of the emergency manager.

The state should focus on state buildings and

facilities that, if damaged or

destroyed by a tornado,

would have statewide effects,

such as critical facilities, transportation

terminals, and state government buildings.

Tornadoes
4-28 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

____

Go to the next hazard on your list to

estimate losses

or if you are finished with all your assessments,

Go to the afterword

____
Version 1.0 August 2001 4-29

estimate losses 4

Task A. Determine the extent of damage from coastal

storms.

There are numerous factors to consider when assessing the vulnerability of buildings in coastal storms. Physical vulnerability refers to

a building’s capacity to withstand:

high-velocity storm surge flooding,

erosion or scour, and

strong winds

For example, the end walls of homes with gabled roofs receive

much of the force of winds, and if trusses are not properly braced,

roofs can fail. However, only a qualified architect or structural

engineer can do more than the most rudimentary analysis of a

building’s structural integrity, so for the purposes of this loss estimate, use common sense strategies for determining a building’s

capacity to withstand wind and water.

1. Calculate losses to structures due to coastal storms.

In assessing physical vulnerability,

the most important factor is the

extent to which structures get

damaged when they are exposed

to water, erosion/scour, high

velocity wind, and debris impact.

Flood Damage. The V Zone Flood

Building Loss Estimation Table

shown at right is an example of

the extent of damage from various

flood depths in coastal V zones on

different kinds of buildings. This

table is from the FEMA BenefitCost Analysis software and has

been compiled based on coastal

damage in the United States. This

table may need to be adjusted for

extenuating circumstances. The V

zone is usually only the first two or

three blocks of homes closest to

the flooding source. You will also

need to assess the vulnerability for

structures in coastal A zones as

Coastal Storms

V Zone Flood Building Loss Estimation Table

Flood depth

(feet)

Building without obstructions

(% building damage)

Building with

obstructions

-0 0 8

-0 0 7

-0 0 6

-0 0 5

-0 0 4

-0 0 3

- 0 2 1 02

- 2 1 1 22

0 51 42

1 32 92

2 53 73

3 05 45

4 85 16

5 36 56

6 76 86

7 07 07

8 27 27

> 6 8 7 67

Source: FEMA Benefit-Cost Analysis Coastal V Zone Module 2/28/99
4-30 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

well. Use the tables beginning on

page 4-13 as the basis to assess the

coastal A zones. You may wish to

increase the figures slightly to

account for greater velocities in

coastal A zones than in riverine A

zones.

Estimate depth of flooding:

Using the information you

gathered previously, estimate

the flood depth at the location you are assessing by

subtracting the lowest floor

elevation from the flood

elevation, as shown in the

illustration.

Determine percent structural damage: Using the V Zone

Flood Building Loss Estimation Table, find the type of

building you’re assessing, match it with the estimated flood

depth, and determine the expected damage to that particular building. For example, a building 4 feet below the base

flood, without any obstructions under the lowest floor, would

be estimated to have 58 percent structural damage. But a

structure with obstructions below the base flood elevation

would result in 61 percent structural damage.

Erosion Damage. Unfortunately, current standard loss estimation

models and tables for erosion damages are not available. As a result,

you may wish to simplify your consideration of structure damage so

that buildings are assumed to be either undamaged or severely

damaged due to erosion. Although slight or moderate damage can

occur due to erosion, the likelihood of this level of damage is

considered small. Your estimated structure loss from erosion should

be based on past experience, the location of the structure within

the hazard area, rate of erosion, and the structure replacement

value.

Wind Damage. There are currently no standard loss estimation

models or tables for wind damage. You should consult with your

building official to help determine the amount of damage to be

expected to your community’s assets as a result of the design wind

speed you determined in Step 2.

2. Calculate losses to contents due to coastal storms.

Building contents are often vulnerable to damage by wind and

water during a coastal storm; therefore, your assessment should take
Version 1.0 August 2001 4-31

estimate losses 4

V Zone Flood Contents Loss Estimation Table

Flood depth

(feet)

Building without obstructions

(% contents damage)

Building with

obstructions

-0 0 8

-0 0 7

-0 0 6

-0 0 5

-0 0 4

-0 0 3

-0 0 2

-6 1 1 1

0 51 42

1 32 92

2 53 73

3 05 45

4 85 16

5 36 56

6 76 86

7 07 07

8 27 27

> 6 8 7 67

Source: FEMA Benefit-Cost Analysis Coastal V Zone Module 2/28/99

V Zone Flood Functional Downtime Table

Flood depth Building without obstructions Building with obstructions

(feet) (functional downtime in days)

-0 0 8

-0 0 7

-0 0 6

-0 0 5

-0 0 4

-0 0 3

- 0 2 1 02

- 2 1 1 22

0 51 42

1 32 92

2 03 03

3 03 03

4 03 03

5 03 03

6 03 03

7 03 03

8 03 03

> 6 8 3 03

Source: FEMA Benefit-Cost Analysis Coastal V Zone Module 2/28/99

into account the fact that contents

on lower levels of buildings may

receive water damage, while those

on upper floors may receive wind

damage. Your risk assessment should

estimate the likely value of contents

within buildings that are similar,

such as residences. You also may

want to conduct site visits to buildings with unique or especially

valuable community assets.

Flood Damage. Using the depth of

flooding determined previously,

find the type of structure you’re

assessing on the V Zone Flood

Contents Loss Estimation Table,

match it with the estimated depth

of flooding for that area of your

community, and determine the

percent contents damage.

Since the contents damage chart

has been established over many

coastal flood events, the values are

for generic contents. If you know

that a particular structure would

endure an extraordinary amount of

contents damage, you should

increase this value. You should also

increase the amount of contents

damage if a residence located in

the floodplain is known to contain

valuable items or if you know an

area is prone to excessively muddy

water or contamination.

Erosion Damage. Again, there are

no standard loss estimation models

and tables for contents damage

from erosion.

Your estimated contents loss should

be based on the structural damage

from erosion, location of the

structure within the hazard area,

and rate of erosion.
4-32 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

States should remember to include the contents

from state owned facilities

that are located in the coastal

floodplain, including vehicles

and equipment.

Wind Damage. There are currently no standard loss estimation

models and tables for contents damage from coastal storm winds.

You should base your estimates on the structural damage from wind,

and the location of the building within the hazard area.

3. Calculate losses to structure use and function due to coastal storms.

In this step you will assess community or state vulnerability in terms

of loss of function. In this area, vulnerability is directly related to

how long a function will be interrupted due to a coastal storm, so

you will estimate how long particular functions in the community

will be interrupted. Depending on the severity of the coastal storm

and the amount of damage a building or other structure is likely to

sustain, it is possible the function could be completely eliminated.

The tables on the previous pages provide a simplified indication of

functional downtime and displacement time for structures due to

various depths of flooding.

Functional Downtime: Using the depth of flooding determined

earlier, find the type of building you’re assessing on the V Zone

Flood Functional Downtime Table, match it with the estimated

depth of flooding for that area of your community, and determine

the function downtime.

V Zone Flood Displacement Time Table

Flood depth Building without obstructions Building with obstructions

(feet) (displacement time in days)

-0 0 8

-0 0 7

-0 0 6

-0 0 5

-0 0 4

-0 0 3

- 0 2 3 0 11

- 6 1 4 2 12

0 07 2 14

1 4 1 2 3 18

2 0 2 6 3 24

3 5 3 5 6 36

4 5 3 5 6 36

5 5 3 5 6 36

6 5 3 5 6 36

7 5 3 5 6 36

8 5 3 5 6 36

> 5 8 3 5 6 36

Source: FEMA Benefit-Cost Analysis Coastal V Zone Module 2/28/99
Version 1.0 August 2001 4-33

estimate losses 4

For example, a building that had 4 feet of flooding is estimated to

result in 30 days of downtime before business can resume in another

location.

Displacement Time: Using the depth of flooding determined earlier,

find the type of building you’re assessing on the V Zone Flood

Displacement Time Table, match it with the estimated depth of

flooding for that area of your community, and determine the

displacement time.

For example, a building that had 4 feet of flooding is estimated to

result in 365 days of displacement time.

4. Calculate human losses due to coastal storms.

Increased development in coastal areas has placed a high number of

people at risk of hurricanes and coastal storms. Fortunately, most

hurricanes and other coastal hazards are predictable and take a

number of days to develop, which allows adequate warning time.

However, deaths still can occur, especially when evacuation orders

are ignored.

____

Go to the next hazard on your list to

estimate losses

or if you are finished with all your assessments

Go to the afterword

____
4-34 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task A. Determine the extent of damage from landslides.

In assessing physical vulnerability, the most important factor is the

extent to which structures get damaged when they are exposed to

landslides. Structures located close to dangerous topographic features such as the tops or bases of slopes or in valleys are at a greater

risk of damage from landslides.

1. Calculate losses to structures due to landslides.

Unfortunately, current standard loss estimation models and tables

only tabulate damages for landslides resulting from earthquakes.

(See the earthquakes resource list in Appendix B or HAZUS for

more information.) Your estimated structure loss should therefore

be based on the location of the structure within the hazard area

and past occurrences of landslides. If you hired a geologist or other

expert to create your community’s landslide hazard map, he or she

may also be able to estimate the potential damage for you. If not,

assessing vulnerability to structures can be simplified so that they are

assumed to be either undamaged or severely damaged due to

landslides. Although slight or moderate damage can occur due to

landslides, the likelihood of this level of damage is considered small.

You may wish to consult with your building official to help estimate

structural damage.

2. Calculate losses to contents due to landslides.

Again, there are no standard loss estimation models and tables for

content damage from landslides.

Your estimated contents loss should be based on the location of the

structure and its contents within the hazard area and past occurrences of landslides.

3. Calculate losses to structure use and function due to landslides.

Vulnerability is directly related to how long a function will be

interrupted due to a landslide. Since there are not any standard

displacement time or functional downtime tables for landslides, you

will estimate how long particular functions in the community will be

interrupted because of a particular level of damage. Go to page 4-4,

“Estimate the losses to structure use and function,” to find specific

advice on how to assess the displacement time and functional

downtime.

The state should focus on landslides that will

block major transportation

routes, bury state-owned facilities, or impact facilities that

would have statewide effects, such as

airports, ports, and critical facilities that

serve large areas.

The acceleration required to initiate slope movement is a complex function of

slope geology, steepness,

groundwater conditions, type

of landslide, and history of previous slope

performance. A generally accepted relationship or simplified methodology for

estimating slope movements has not

been developed yet.

Landslides
Version 1.0 August 2001 4-35

estimate losses 4

4. Calculate human losses due to landslides.

In the event that an area is subject to earthquakes, rapid snowmelt,

or mudflows, or where there are insufficient warning systems, it is

possible that deaths can occur, especially if roads are damaged. You

may need to rely on statistics from past landslides in your area to

determine the vulnerability of the population to landslides.

____

Go to the next hazard on your list to

estimate losses

or if you are finished with all your assessments

Go to the afterword

____
4-36 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Task A. Determine the extent of damage from wildfires.

In assessing physical vulnerability, the most important factor is the

extent to which structures get damaged when they are exposed to

fire and heat. Structures located near the urban-wildland interface

area are at the greatest risk of damage from wildfires.

1. Calculate losses to structures due to wildfires.

Current standard loss estimation tables do not exist for wildfires.

You may wish to contact your local fire department to help estimate

structural vulnerability.

2. Calculate losses to contents due to wildfires.

There are not any standard loss estimation models and tables for

contents damage. Assumptions about damage to contents should be

increased for contents that are sensitive to heat such as electronics,

and contents that would be damaged as a result of the fire suppression efforts (i.e., water damage) such as books or paper files.

3. Calculate losses to structure use and function due to wildfires.

Vulnerability is directly related to how long a function will be

interrupted due to a wildfire. Since there are no standard displacement time or functional downtime tables for wildfires, you will need

to estimate how long particular functions will be interrupted because of a wildfire hazard event. Go to page 4-4, “Estimate the losses

to structure use and function,” to find specific advice on how to

assess the displacement time and functional downtime.

4. Calculate human losses due to wildfires.

Most wildfire related deaths occur as the result of fire suppression

activities. However, if roads are damaged or there is insufficient

warning time, other injuries and deaths can occur. Since there are

no death or injury curves for wildfires, estimate the number of

injuries or deaths based on past wildfire events.

____

Go to the next hazard on your list to

estimate losses

or if you are finished with all your assessments

Go to the afterword

____

States should focus

on state buildings and facilities that, if damaged or destroyed by wildfires, would

have statewide effects. Contact your state forester or the U.S. Forest Service (see Appendix B).

Use the Wildfire Hazard Rating Form on

page 4-37 to calculate the

hazard to subdivisions within

the community. You may also

wish to use it to evaluate all areas near

the urban wildland interface. Contact your

local fire department or engineer for assistance with this form.

Wildfires
Version 1.0 August 2001 4-37

estimate losses 4

Wildfire Hazard Rating Form

-SubdivisionName of Subdivision __________________________________________________ Date __________________

County ________________Size (Acres) ______________________________ #Lots ______________________

Rating _________________ Comments _________________________________________________________

C. Topography Points

1. Predominant Slope

8% or less....................................... 1 __________

More than 8%, but less than 20%... 4 __________

20% or more, but less than 30% .... 7 __________

30% or more ................................... 10 _________

D. Roofing Material

Class A Rated................................. 1 __________

Class B Rated................................. 3 __________

Class C Rated ................................ 5 __________

Non-Rated....................................... 10 _________

E. Fire Protection – Water Source

500 GPM Hydrant within 1,000 feet ...... 1 __________

Hydrant farther than 1,000 feet or draft

site ........................................................ 2 __________

Water source within 20 minutes or

less, round trip ...................................... 5 __________

Water source farther than 20 minutes,

and but less than 45 minutes round trip 7 __________

Water source farther than 45 minutes

round trip ............................................... 10 _________

F. Existing Building Construction

Materials

Noncombustible siding/deck ................. 1 __________

Noncombustible siding/combustible

deck ...................................................... 5 __________

Combustible siding and deck ................ 10 _________

G. Utilities

All underground utilities ......................... 1 __________

One underground, one above ground .... 3 __________

All above ground ................................... 5 __________

TOTAL FOR SUBDIVISION ___________

___________________________________________

RATING SCALE:

MODERATE HAZARD 40-59

HIGH HAZARD 60-74

EXTREME HAZARDS 75+

A. Subdivision Design Points

1. Ingress/Egress

Two or more primary roads ............ 1 __________

One Road ........................................ 3 __________

One-way in, one-way out ................ 5 __________

2. Width of Primary Road ......................

20 feet or more ............................... 1 __________

20 feet or less ................................. 3 __________

3. Accessibility ......................................

Road Grade 5% or less .................. 1 __________

Road Grade 5% or more ................. 3 __________

4. Secondary Road Terminus: ...............

Loop roads, cul-de-sacs with

outside turning radius of 45 feet

or greater ........................................ 1 __________

Cul-de-sac turnaround radius

is less than 45 feet ......................... 2 __________

Dead-end roads 200 feet or less

in length .......................................... 3 __________

Dead-end roads greater than

200 feet in length ............................ 5 __________

5. Average lot size

10 acres or larger ........................... 1 __________

Larger than 1 acre, but less than

10 acres .......................................... 3 __________

1 acre or less .................................. 5 __________

6. Street signs

Present ........................................... 1 __________

Not present ..................................... 5 __________

B. Vegetation

1. Fuel Types

Light ................................................ 1 __________

Medium ........................................... 5 __________

Heavy ............................................. 10 _________

2. Defensible Space

70% or more of site ........................ 1 __________

30% or more, but less than 70% .... 3 __________

Less than 30% of site ..................... 5 __________

Source: Urban Wildland Interface Code, 2000

Click to proceed to

Afterword

Return to

Table of Contents
afterword
Version 1.0 August 2001 afterword

afterword

As detailed in the Foreword,

the Natural Hazard Mitigation Planning

process consists of four basic phases.

You have completed your loss estimate.

Now what?

Your loss estimate is the foundation upon which you will

develop a state or local mitigation plan. With it, you should be

able to identify what areas of your community or state are susceptible to each hazard, where the highest losses would occur, how

much a hazard may cost were it to occur, and how the lives and

quality of life in your community or state might be affected in the

aftermath of a disaster. You also now have a factual basis for developing a mitigation strategy for your community or state. This will be

important data necessary to support future mitigation decisions.

It is therefore important to compile the results of your work into a

written report. This report should be presented to citizens and

elected officials. The State Hazard Mitigation Officer should be

aware of the completion of your loss estimate because the State

may want to use it as part of its statewide risk assessment.

The results of your risk assessment will likely draw interest from a

wide range of sectors in the community or state. Business owners

and residents will want to know what the results of the risk assessment mean for them and what to do next. You have an opportunity

to use the results of the risk assessment as a tool to galvanize the

community and to secure interest and support for the remainder

of the hazard mitigation planning process. The risk assessment can

be an effective tool for public education, disaster response and

recovery, and economic development. For example, you can use

the results of the risk assessment to:

 Promote flood insurance by targeting at-risk properties;

 Support a public hazard awareness initiative;

 Encourage elected officials to approve and implement a

hazard mitigation plan;

 Support economic development decisions by allowing

hazards to be mitigated when new development takes

place; and

The next how-to in the series, Develop

a Mitigation Plan, will directly build on

the work you have just completed.
afterword STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

 Reduce costs spent on disaster response and recovery

through pre-identification of at-risk populations or

areas, and implementation of mitigation initiatives.

By gathering information from a variety of state and local resources, you have begun to forge relations within your community

and state that will continue to be nurtured throughout the planning process.

In the next phase of the Natural Hazard Mitigation Planning

Process, Develop a Mitigation Plan, you will find solutions to address

the potential impacts of natural hazards in your community or

state by developing a strategy to reduce the effects of the hazards.

The mitigation strategy will be based on the risk assessment you

just completed in the second phase of the Natural Hazard Mitigation Planning process and will provide a comprehensive strategy to

address the mitigation priorities within your community or state.

Click to proceed to

Appendix A

Return to

Table of Contents
Version 1.0 August 2001 a-1

appendix a

glossary

Acceleration

Asset

Base Flood

Base Flood Elevation (BFE)

Bedrock

Building

Coastal High Hazard Area

Coastal Zones

Community Rating System

(CRS)

Computer-Aided Design And

Drafting (CADD)

Contour

The rate of change of velocity with respect to time. Acceleration due to gravity

at the earth's surface is 9.8 meters per second squared. That means that every

second that something falls toward the surface of earth its velocity increases

by 9.8 meters per second.

Any manmade or natural feature that has value, including, but not limited to

people; buildings; infrastructure like bridges, roads, and sewer and water

systems; lifelines like electricity and communication resources; or environmental, cultural, or recreational features like parks, dunes, wetlands, or

landmarks.

Flood that has a 1 percent probability of being equaled or exceeded in any

given year. Also known as the 100-year flood.

Elevation of the base flood in relation to a specified datum, such as the

National Geodetic Vertical Datum of 1929. The Base Flood Elevation is used

as the standard for the National Flood Insurance Program.

The solid rock that underlies loose material, such as soil, sand, clay, or gravel.

A structure that is walled and roofed, principally above ground and permanently affixed to a site. The term includes a manufactured home on a permanent foundation on which the wheels and axles carry no weight.

Area, usually along an open coast, bay, or inlet, that is subject to inundation

by storm surge and, in some instances, wave action caused by storms or

seismic sources.

The area along the shore where the ocean meets the land as the surface of

the land rises above the ocean. This land/water interface includes barrier

islands, estuaries, beaches, coastal wetlands, and land areas having direct

drainage to the ocean.

An NFIP program that provides incentives for NFIP communities to complete

activities that reduce flood hazard risk. When the community completes

specified activities, the insurance premiums of policyholders in these communities are reduced.

A computerized system enabling quick and accurate electronic 2-D and 3-D

drawings, topographic mapping, site plans, and profile/cross-section drawings.

A line of equal ground elevation on a topographic (contour) map.
a-2 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Critical Facility

Debris

Digitize

Displacement Time

Duration

Earthquake

Erosion

Erosion Hazard Area

Essential Facility

Extent

Extratropical Cyclone

Fault

Federal Emergency Management

Agency (FEMA)

Facilities that are critical to the health and welfare of the population

and that are especially important following hazard events. Critical

facilities include, but are not limited to, shelters, police and fire stations,

and hospitals.

The scattered remains of assets broken or destroyed in a hazard event.

Debris caused by a wind or water hazard event can cause additional

damage to other assets.

To convert electronically points, lines, and area boundaries shown on

maps into x, y coordinates (e.g., latitude and longitude, universal

transverse mercator (UTM), or table coordinates) for use in computer

applications.

The average time (in days) which the building's occupants typically must

operate from a temporary location while repairs are made to the original

building due to damages resulting from a hazard event.

How long a hazard event lasts.

A sudden motion or trembling that is caused by a release of strain

accumulated within or along the edge of earth's tectonic plates.

Wearing away of the land surface by detachment and movement of soil

and rock fragments, during a flood or storm or over a period of years,

through the action of wind, water, or other geologic processes.

Area anticipated to be lost to shoreline retreat over a given period of

time. The projected inland extent of the area is measured by multiplying

the average annual long-term recession rate by the number of years

desired.

Elements that are important to ensure a full recovery of a community or

state following a hazard event. These would include: government

functions, major employers, banks, schools, and certain commercial

establishments, such as grocery stores, hardware stores, and gas stations.

The size of an area affected by a hazard or hazard event.

Cyclonic storm events like Nor'easters and severe winter low-pressure

systems. Both West and East coasts can experience these non-tropical

storms that produce gale-force winds and precipitation in the form of

heavy rain or snow. These cyclonic storms, commonly called Nor'easters

on the East Coast because of the direction of the storm winds, can last

for several days and can be very large – 1,000-mile wide storms are not

uncommon.

A fracture in the continuity of a rock formation caused by a shifting or

dislodging of the earth's crust, in which adjacent surfaces are differentially displaced parallel to the plane of fracture.

Independent agency created in 1978 to provide a single point of accountability for all Federal activities related to disaster mitigation and

emergency preparedness, response and recovery.
appendix a – glossary

Version 1.0 August 2001 a-3

Fire Potential Index (FPI)

Flash Flood

Flood

Flood Depth

Flood Elevation

Flood Hazard Area

Flood Insurance Rate Map (FIRM)

Flood Insurance Study (FIS)

Floodplain

Frequency

Fujita Scale of Tornado Intensity

Functional Downtime

Geographic Area Impacted

Developed by USGS and USFS to assess and map fire hazard potential

over broad areas. Based on such geographic information, national policy

makers and on-the-ground fire managers established priorities for

prevention activities in the defined area to reduce the risk of managed

and wildfire ignition and spread. Prediction of fire hazard shortens the

time between fire ignition and initial attack by enabling fire managers to

pre-allocate and stage suppression forces to high fire risk areas.

A flood event occurring with little or no warning where water levels rise

at an extremely fast rate.

A general and temporary condition of partial or complete inundation of

normally dry land areas from (1) the overflow of inland or tidal waters,

(2) the unusual and rapid accumulation or runoff of surface waters from

any source, or (3) mudflows or the sudden collapse of shoreline land.

Height of the flood water surface above the ground surface.

Elevation of the water surface above an established datum, e.g. National

Geodetic Vertical Datum of 1929, North American Vertical Datum of

1988, or Mean Sea Level.

The area shown to be inundated by a flood of a given magnitude on a

map.

Map of a community, prepared by the Federal Emergency Management

Agency, that shows both the special flood hazard areas and the risk

premium zones applicable to the community.

A study that provides an examination, evaluation, and determination of

flood hazards and, if appropriate, corresponding water surface elevations in a community or communities.

Any land area, including watercourse, susceptible to partial or complete

inundation by water from any source.

A measure of how often events of a particular magnitude are expected to

occur. Frequency describes how often a hazard of a specific magnitude,

duration, and/or extent typically occurs, on average. Statistically, a

hazard with a 100-year recurrence interval is expected to occur once

every 100 years on average, and would have a 1 percent chance – its

probability – of happening in any given year. The reliability of this

information varies depending on the kind of hazard being considered.

Rates tornadoes with numeric values from F0 to F5 based on tornado

windspeed and damage sustained. An F0 indicates minimal damage such

as broken tree limbs or signs, while and F5 indicated severe damage

sustained.

The average time (in days) during which a function (business or service)

is unable to provide its services due to a hazard event.

The physical area in which the effects of the hazard are experienced.
a-4 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Geographic Information

Systems (GIS)

Ground Motion

Hazard

Hazard Event

Hazard Identification

Hazard Mitigation

Hazard Profile

HAZUS (Hazards U.S.)

Hurricane

Hydrology

Infrastructure

Intensity

Landslide

A computer software application that relates physical features on the

earth to a database to be used for mapping and analysis.

The vibration or shaking of the ground during an earthquake. When a

fault ruptures, seismic waves radiate, causing the ground to vibrate. The

severity of the vibration increases with the amount of energy released

and decreases with distance from the causative fault or epicenter, but

soft soils can further amplify ground motions

A source of potential danger or adverse condition. Hazards in this howto series will include naturally occurring events such as floods, earthquakes, tornadoes, tsunami, coastal storms, landslides, and wildfires that

strike populated areas. A natural event is a hazard when it has the

potential to harm people or property.

A specific occurrence of a particular type of hazard.

The process of identifying hazards that threaten an area.

Sustained actions taken to reduce or eliminate long-term risk from

hazards and their effects.

A description of the physical characteristics of hazards and a determination of various descriptors including magnitude, duration, frequency,

probability, and extent. In most cases, a community can most easily use

these descriptors when they are recorded and displayed as maps.

A GIS-based nationally standardized earthquake loss estimation tool

developed by FEMA.

An intense tropical cyclone, formed in the atmosphere over warm ocean

areas, in which wind speeds reach 74-miles-per-hour or more and blow in

a large spiral around a relatively calm center or "eye." Hurricanes

develop over the north Atlantic Ocean, northeast Pacific Ocean, or the

south Pacific Ocean east of 160°E longitude. Hurricane circulation is

counter-clockwise in the Northern Hemisphere and clockwise in the

Southern Hemisphere.

The science of dealing with the waters of the earth. A flood discharge is

developed by a hydrologic study.

Refers to the public services of a community that have a direct impact

on the quality of life. Infrastructure includes communication technology

such as phone lines or Internet access, vital services such as public water

supplies and sewer treatment facilities, and includes an area's transportation system such as airports, heliports; highways, bridges, tunnels,

roadbeds, overpasses, railways, bridges, rail yards, depots; and waterways,

canals, locks, seaports, ferries, harbors, drydocks, piers and regional

dams.

A measure of the effects of a hazard event at a particular place.

Downward movement of a slope and materials under the force of gravity.
appendix a – glossary

Version 1.0 August 2001 a-5

Develop on gentle slopes and entail the sidelong movement of large

masses of soil as an underlying layer liquefies in a seismic event.

The phenomenon that occurs when ground shaking causes loose soils to

lose strength and act like viscous fluid. Liquefaction causes two types of

ground failure: lateral spread and loss of bearing strength.

Results when the soil supporting structures liquefies. This can cause

structures to tip and topple.

Under the NFIP, the lowest floor of the lowest enclosed area (including

basement) of a structure.

A measure of the strength of a hazard event. The magnitude (also

referred to as severity) of a given hazard event is usually determined

using technical measures specific to the hazard.

A systematic evaluation of the nature and extent of vulnerability to the

effects of natural hazards typically present in the state and includes a

description of actions to minimize future vulnerability to hazards.

Federal program created by Congress in 1968 that makes flood insurance available in communities that enact minimum floodplain management regulations in 44 CFR §60.3.

Datum established in 1929 and used in the NFIP as a basis for measuring

flood, ground, and structural elevations, previously referred to as Sea

Level Datum or Mean Sea Level. The Base Flood Elevations shown on

most of the Flood Insurance Rate Maps issued by the Federal Emergency

Management Agency are referenced to NGVD.

Prepares and issues flood, severe weather, and coastal storm warnings

and can provide technical assistance to Federal and state entities in

preparing weather and flood warning plans.

An extra-tropical cyclone producing gale-force winds and precipitation

in the form of heavy snow or rain.

Follows water inundation creating strong currents that rip at structures

and pound them with debris, and erode beaches and coastal structures.

Describes maps that indicate only man-made features like buildings.

The act or process of making or carrying out plans; the establishment of

goals, policies and procedures for a social or economic unit.

A statistical measure of the likelihood that a hazard event will occur.

The time between hazard events of similar size in a given location. It is

based on the probability that the given event will be equaled or exceeded in any given year.

A property that is currently insured for which two or more National

Flood Insurance Program losses (occurring more than ten days apart) of

at least $1000 each have been paid within any 10-year period since 1978.

Lateral Spreads

Liquefaction

Loss of Bearing Strength

Lowest Floor

Magnitude

Mitigation Plan

National Flood Insurance Program

(NFIP)

National Geodetic Vertical Datum

of 1929 (NGVD)

National Weather Service (NWS)

Nor'easter

Outflow

Planimetric

Planning

Probability

Recurrence Interval

Repetitive Loss Property
a-6 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

The cost of rebuilding a structure. This is usually expressed in terms of

cost per square foot, and reflects the present-day cost of labor and

materials to construct a building of a particular size, type and quality.

A numerical scale of earthquake magnitude devised by seismologist C.F.

Richter in 1935.

The estimated impact that a hazard would have on people, services,

facilities, and structures in a community; the likelihood of a hazard

event resulting in an adverse condition that causes injury or damage.

Risk is often expressed in relative terms such as a high, moderate or low

likelihood of sustaining damage above a particular threshold due to a

specific type of hazard event. It also can be expressed in terms of potential monetary losses associated with the intensity of the hazard.

Of or produced by a river.

A proportion used in determining a dimensional relationship; the ratio

of the distance between two points on a map and the actual distance

between the two points on the earth's surface.

A steep slope.

Removal of soil or fill material by the flow of flood waters. The term is

frequently used to describe storm-induced, localized conical erosion

around pilings and other foundation supports where the obstruction of

flow increases turbulence.

Describes the likelihood of an area being subject to earthquakes.

An area within a floodplain having a 1 percent or greater chance of

flood occurrence in any given year (100-year floodplain); represented

on Flood Insurance Rate Maps by darkly shaded areas with zone designations that include the letter A or V.

The Robert T. Stafford Disaster Relief and Emergency Assistance Act, PL

100-107 was signed into law November 23, 1988 and amended the

Disaster Relief Act of 1974, PL 93-288. The Stafford Act is the statutory

authority for most Federal disaster response activities, especially as they

pertain to FEMA and its programs.

The representative of state government who is the primary point of

contact with FEMA, other state and Federal agencies, and local units of

government in the planning and implementation of pre- and postdisaster mitigation activities.

Rise in the water surface above normal water level on the open coast due

to the action of wind stress and atmospheric pressure on the water

surface.

Something constructed. (See also Building)

Replacement Value

Richter Scale

Risk

Riverine

Scale

Scarp

Scour

Seismicity

Special Flood Hazard Area (SFHA)

Stafford Act

State Hazard Mitigation Officer

(SHMO)

Storm Surge

Structure
appendix a – glossary

Version 1.0 August 2001 a-7

Damage of any origin sustained by a structure in a Special Flood Hazard

Area whereby the cost of restoring the structure to its before-damaged

condition would equal or exceed 50 percent of the market value of the

structure before the damage.

A typhoon with maximum sustained winds of 150 mph or more.

The differential movement of two sides of a fracture – in other words,

the location where the ground breaks apart. The length, width, and

displacement of the ground characterize surface faults.

Torsionally rigid, thin segments of the earth's lithosphere that may be

assumed to move horizontally and adjoin other plates. It is the friction

between plate boundaries that cause seismic activity.

Characterizes maps that show natural features and indicate the physical

shape of the land using contour lines. These maps may also include

manmade features.

A violently rotating column of air extending from a thunderstorm to the

ground.

A generic term for a cyclonic, low-pressure system over tropical or subtropical waters.

A tropical cyclone with maximum sustained winds of less than 39 mph.

A tropical cyclone with maximum sustained winds greater than 39 mph

and less than 74 mph.

Great sea wave produced by submarine earth movement or volcanic

eruption.

A special category of tropical cyclone peculiar to the western North

Pacific Basin, frequently affecting areas in the vicinity of Guam and the

North Mariana Islands. Typhoons whose maximum sustained winds

attain or exceed 150 mph are called super typhoons.

Describes how exposed or susceptible to damage an asset is. Vulnerability depends on an asset's construction, contents, and the economic value

of its functions. Like indirect damages, the vulnerability of one element

of the community is often related to the vulnerability of another. For

example, many businesses depend on uninterrupted electrical power –

if an electric substation is flooded, it will affect not only the substation

itself, but a number of businesses as well. Often, indirect effects can be

much more widespread and damaging than direct ones.

The extent of injury and damage that may result from a hazard event of

a given intensity in a given area. The vulnerability assessment should

address impacts of hazard events on the existing and future built environment.

Substantial Damage

Super Typhoon

Surface Faulting

Tectonic Plate

Topographic

Tornado

Tropical Cyclone

Tropical Depression

Tropical Storm

Tsunami

Typhoon

Vulnerability

Vulnerability Assessment
a-8 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

When a large mass of earth on the ocean bottom sinks or uplifts, the

column of water directly above it is displaced, forming the tsunami wave.

The rate of displacement, motion of the ocean floor at the epicenter,

the amount of displacement of the rupture zone, and the depth of water

above the rupture zone all contribute to the intensity of the tsunami.

The height that the wave extends up to on steep shorelines, measured

above a reference level (the normal height of the sea, corrected to the

state of the tide at the time of wave arrival).

An uncontrolled fire spreading through vegetative fuels, exposing and

possibly consuming structures.

A geographical area shown on a Flood Insurance Rate Map (FIRM) that

reflects the severity or type of flooding in the area.

Water Displacement

Wave Runup

Wildfire

Zone

Click to proceed to

Appendix B

Return to

Table of Contents
Version 1.0 August 2001 b-1

appendix b

library

Federal Emergency Management Agency (FEMA)

FEMA Publications Warehouse

FEMA Mitigation Planning

American Planning Association

Institute for Business and Home Safety

National Hurricane Center

National Institute of Building Sciences (NIBS)

National Institute of Standards and Technology (NIST)

National Oceanographic and Atmospheric

Administration (NOAA)

National Weather Service

U.S. Army Corps of Engineers Regional Sites and

Districts

United States Geological Survey (USGS) Homepage

identify hazards

American Red Cross – local chapters

Disaster Center

Digital Q3 Flood Data

ESRI

Federal Emergency Management Agency

http://www.fema.gov

FEMA Headquarters:

500 C Street, SW, Washington, D.C. 20472

Phone: (202) 646-4600

800-480-2520

http://www.fema.gov/fima/planning.htm

http://www.planning.org

http://www.ibhs.org

http://www.nhc.noaa.gov

http://www.nibs.org/

http://www.nist.gov

http://www.noaa.gov

http://www.nws.noaa.gov

http://www.usace.army.mil/

organizations.htm#Divisions

http://www.usgs.gov/ (888-ASK-USGS)

http://www.redcross.org/where/where.html

http://www.disastercenter.com

http://msc.fema.gov/MSC/statemap.htm

http://www.esri.com/hazards

Multi-Hazard Identification and Risk Assessment: A

Cornerstone of the National Mitigation Strategy. 1997

Planning for Post-Disaster Recovery and Reconstruction. FEMA and American Planning Association.

Planning Advisory Service (PAS) Report Number 483/

484. 1998.

1

General Contact Information
b-2 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Landslide Risk Areas

National Weather Service (NWS) – Regional Offices

Natural Hazards Center

Natural Hazards Statistics

NOAA, Central Library

NOAA, National Geophysical Data Center

State Emergency Management Agencies

State Geologists

State Hazard Mitigation Officers

State Historic Preservation Officers

Tsunami Hazard Mitigation

U.S. Geological Survey

Wildfire Danger Conditions

Wind Zones

World Wide Weather and Climate Events

profile hazard events

Association of State Dam Safety Officials

Coastal and lake bathymetry and climate –

NOAA National Data Center

Elevation, hydrology, land use, transportation, etc. –

USGS National Mapping Information

Endangered species, etc. –

U.S. National Biological Information Infrastructure

Federal Lands – Bureau of Land Management (BLM)

Geospatial Home Page

http://landslides.usgs.gov/html_files/

landslides/nationalmap/national.html

http://weather.gov/organization.html

http://www.Colorado.EDU/hazards/sites/

costs.html

http://www.noaa.gov/om/hazstats.shtml

http://www.lib.noaa.gov

http://www.ngdc.noaa.gov/seg/hazard/

resource

http://www.fema.gov/fema/statedr.shtm

http://www.ak-prepared.com/statelinks.htm

http://www.kgs.ukans.edu/AASG/AASG.html

http://www.floods.org/shmos.htm

http://www.hazmit.net/

http://www.sso.org/ncshpo/shpolist.htm

http://www.pmel.noaa.gov/~bernard/

senatec.html

http://geohazards.cr.usgs.gov/

http://www.fs.fed.us/land/wfas/fd_class.gif

http://www.fema.gov/graphics/library/wmap.gif

http://www.ncdc.noaa.gov/ol/reports/

weather-events.html#STORM

http://www.damsafety.org

http://www.ngdc.noaa.gov/mgg/bathymetry

http://mapping.usgs.gov

http://www.nbii.gov

http://www.blm.gov/gis

2
appendix b – library

Version 1.0 August 2001 b-3

http://www.fema.gov/maps/

http://www.fema.gov/nfip/fmapinfo.htm

http://www.stateforesters.org/sflist.html

http://www.fs.fed.us/intro/directory/orgdir.html

http://www.fs.fed.us

http://www.fema.gov/hazus/

HAZUS99 User's Manual and HAZUS99 Technical

Manual, Vols. 1, 2, & 3. FEMA-366

http://www.nps.gov/gis

http://www.nwi.fws.gov

http://msc.fema.gov/MSC/hardcopy.htm

http://www.floods.org/stcoor.htm

http://geohazards.cr.usgs.gov/eq

http://www.csc.noaa.gov/products/nchaz/htm/

dinfo_6.htm

http://www.usace.army.mil/

http://www.fs.fed.us/land/wfas/nfdr_map.htm

http://www.statlab.iastate.edu/soils/nsdaf

http://mapping.usgs.gov/mac/nimamaps/topo.html

http://mcmcweb.er.usgs.gov/topomaps/

http://stats.bls.gov/datahome.htm

http://factfinder.census.gov/servlet/BasicFactsServlet

http://www.census.gov/geo/www/tiger/

http://woodrow.mpls.frb.fed.us/research/data/us/

calc/

Guidance on Estimating Substantial Damage. FEMA311

FEMA Map Service Center

Flood Risk and Map Information

Forestry Service Contacts

State:

Regional:

GIS Data Sources for Forest Areas –

USDA Forest Service (USFS)

HAZUS instruction and technical information

National parks – National Park Service (NPS)

National Wetlands Inventory –

U.S. Fish and Wildlife Service (USFWS)

NFIP Guide to Flood Maps

NFIP State Coordinators

Seismic hazards –

USGS National Seismic Hazard Mapping Project

Spatial Data Resources by State

U.S. Army Corps of Engineers

USDA Wildfire Fuel Model Map

USDA Natural Resource Conservation Service

(NRCS) – National Cartography and Geospatial

Center (NCGC)

USGS Topographic Maps

inventory assets

Bureau of Labor Statistics

Census Information

Consumer Price Index

FEMA Publication on Substantial

Damage

3
b-4 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

http://www.fema.gov/hazus/

HAZUS99 User's Manual and HAZUS99

Technical Manual, Vols. 1, 2, & 3. FEMAhttp://www.csc.noaa.gov/products/nchaz/

htm/dinfo_4.htm

http://www.nhq.nrcs.usda.gov/

Building Construction Cost Data, 2001.

Means. 2001.

Repair & Remodeling Cost Data, Commercial,

Residential. Means. 1999.

Residential Cost Data, 2000. Means. Howard

M. Chandler (Editor). 2000.

HAZUS instruction and technical information

Socio-Economic Data Resources

USDA, Natural Resources Conservation Service

assess risk

Building construction costs.

Commercial and residential cost per square foot.

Residential cost per square foot.

4

Floods

Association of State Dam Safety Officials

Copies of FIRMs, FISs, DFIRMs, Digital Q3 Flood

Data, and FHBMs

Flash-Flood Safety Rules

Flood Risk and Map Information

Flood Safety Rules

Floodplain Management Association

General Flood Information

Guide to Flood Maps on the web

Latest hydrological information (flooding, droughts, snow

conditions, and water supply)

http://www.damsafety.org/

http://www.fema.gov/maps/

FEMA Map Service Center 800.358.9616

http://srh.noaa.gov/oun/severewx/safety.html#flashflood

http://www.fema.gov/nfip/fmapinfo.htm

http://www.nws.noaa.gov/om/brochures/nh-flood.htm

http://www.floodplain.org

http://www.nfpa.org/Education/

TalkingAboutDisaster/FloodFlash/

FloodFlash.asp 

http://msc.fema.gov/MSC/hardcopy.htm

http://www.nws.noaa.gov/oh/hic/conds.html

General Hazard Information
appendix b – library

Version 1.0 August 2001 b-5

http://water.usgs.gov/realtime.html

http://www.crh.noaa.gov/ahps/rfc.html

http://www.floods.org/stcoor.htm

http://www.usace.army.mil/inet/functions/cw

http://water.usgs.gov/usa/nwis/sw

http://www.bssconline.org

http://www.consrv.ca.gov/dmg/shezp/index.htm

http://wwwneic.cr.usgs.gov/neis/states/states.html

http://www.abag.ca.gov/bayarea/eqmaps/

eqmaps.html

http://www.fema.gov/hazus/

Rapid Visual Screening of Buildings for Potential

Seismic Hazards: A Handbook. FEMA-154. Supporting documentation. FEMA-155.

NEHRP Handbook for the Seismic Evaluation of

Existing Buildings: A Pre-Standard. FEMA-310.

http://geohazards.cr.usgs.gov/eq/html/genmap.html

http://quake.wr.usgs.gov/

http://geohazards.cr.usgs.gov/eq

http://eqint.cr.usgs.gov/eq/html/custom.shtml

United States Geological Survey 888-ASK-USGS

http://www.nfpa.org/Education/

TalkingAboutDisaster/Tsunami/

tsunami..asp

http://www.pmel.noaa.gov/tsunami-hazard/

503.731.4100

800 NE Oregon Street, #28

Portland OR 97232

http://www.pmel.noaa.gov

Real-time hydrologic data page

Regional River Forecast Centers

State Floodplain Managers

United States Army Corps of Engineers (USACE)

USGS Streamflow Data Historical

Earthquakes

Building Seismic Safety Council

California Division of Mines and Geology

Earthquake hazard history, by state

Earthquake maps and information

FEMA HAZUS homepage

FEMA Publications

GIS data available on earthquakes

USGS Earthquake homepage

USGS National and regional custom earthquake risk

maps

Tsunamis

General Tsunami Information

National Tsunami Hazard Mitigation Program

Oregon Department of Geology and Mineral Industries

(DOGAMI)

Pacific Marine Environmental Laboratory
b-6 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Pacific Tsunami Warning Center

Tsunami Inundation Mapping

U.S.Geological Survey

University of Washington

West Coast/Alaska Tsunami Warning Center of NOAA/NWS

Tornadoes

ASCE Wind Speed Maps

General Tornado Information

Tornado Project Online

Tornado Safe Room Program

Coastal Storms

500-year and 100-year return peak

gust hurricane wind speeds

ASCE Wind Speed Maps

Coastal zone management programs by state

FAQ: Hurricanes, Typhoons, and Tropical Storms

FEMA Publications

808.689.8207

91-270 Fort Weaver Road

Ewa Beach HI 96706

http://newport.pmel.noaa.gov/time/reports/

may2000stat.html

http://www.usgs.gov/themes/coast.html

http://www.geophys.washington.edu

907.745.4212

910 S. Felton Street

Palmer AK 99645-6552

http://www.ascepub.infor.com/windload.html

http://www.nfpa.org/Education/

TalkingAboutDisaster/Tornado/

tornado.asp

http://www.tornadoproject.com

http://www.fema.gov/mit/saferoom/

http://www.fema.gov/hazards/hurricanes/hurfacts.shtm

http://www.ascepub.infor.com/windload.html

http://www.ocrm.nos.noaa.gov/czm/

czmsitelist.html

http://www.aoml.noaa.gov/hrd/tcfaq/

tcfaqG.html#G12

Coastal Construction Manual. FEMA-55

Multihazard Identification and Risk Assessment. http://www.fema.gov/mit/tsd/

ft_mhira.htm

Evaluation of Erosion Hazards. The Heinz

Center. http://www.fema.gov/nwz00/

erosion.shtm
appendix b – library

Version 1.0 August 2001 b-7

General Hurricane Information

Great Lakes Commission

Historical data and maps on past hurricane tracks

Hurricane Safety Rules

Inland Wind Model estimates maximum winds of

landfalling hurricanes

United States Army Corps of Engineers (USACE)

Landslides

American Planning Association –

Landslide Hazards and Planning

General Landslide Information

How to do landslide hazard analysis

Landslide and Mudflow Fact Sheet

Landslide hazard maps (San Francisco Bay Area)

Landslide overview map of US

Wildfires

Firewise

General Wildfire Information

Local wildfire observations and trend forecasts

for fire weather forecasts zones.

NOAA Fire Event Satellite Photos

http://www.nfpa.org/Education/

TalkingAboutDisaster/Hurricane/

hurricane.asp

http://www.glc.org

http://www.nhc.noaa.gov/pastall.html

http://www.nws.noaa.gov/om/brochures/nh-hurr.htm

http://www.nhc.noaa.gov/aboutmeow.html

http://www.usace.army.mil/inet/functions/cw

http://www.planning.org/Landslides

http://www.nfpa.org/Education/

TalkingAboutDisaster/Landslide/

Landslide.asp

http://www.itc.nl/ilwis/

http://www.fema.gov/hazards/landslides/landslif.shtm

http://wrgis.wr.usgs.gov/open-file/of97-745

http://landslide.usgs.gov/html_files/landslides/

nationalmap/national.html

http://landslides.usgs.gov/html_files/nlic/

maporder.html

http://www.firewise.org

http://www.nfpa.org/Education/

TalkingAboutDisaster/Wildfire/

wildfire.asp

http://www.fs.fed.us/land/wfas/fd_class.gif

http://www.osei.noaa.gov/Events/Fires/
b-8 STATE AND LOCAL MITIGATION PLANNING how-to guide: Understanding Your Risks

Resolution Fire Danger Rating Fuel Model Map

U. S. Forest Service, USDA

USGS Topographic Maps

Wildland Fire Assessment System

Wildland Fire Updates

Other Hazards

Avalanches

Dam Safety

Dam Safety Program – FEMA

Drought – USDA

Drought – USGS

Extreme Heat Fact Sheet

General Heat Wave Information

General Severe Thunderstorm Information

General Volcano Information

General Winter Storm Information

National Severe Weather Laboratory estimates the likelihood

of severe thunderstorm hazards in the United States.

Smithsonian Institution Global Volcanism Program

Snow and Ice – National Snow and Ice Data Center, University

of Colorado

Volcano Hazard Maps

http://www.fs.fed.us/land/wfas/nfdr_map.htm

http://www.fs.fed.us/

http://mcmcweb.er.usgs.gov/topomaps/

http://www.fs.fed.us/land/wfas/

http://www.nifc.gov/fireinfo/nfn.html

http://www.avalanche.org

http://www.usbr.gov/laws/damguide.html

http://www.fema.gov/fima/damsafe/

http://www.drought.unl.edu/dm/index.html

http://www.usgs.gov

http://www.fema.gov/hazards/extremeheat/heatf.shtm

http://www.nfpa.org/Education/

TalkingAboutDisaster/HeatWave/

HeatWave.asp

http://www.nfpa.org/Education/

TalkingAboutDisaster/Thunderstorm/

Thunderstorm.asp

http://www.nfpa.org/Education/

TalkingAboutDisaster/Volcano/

volcano.asp

http://www.nfpa.org/Education/

TalkingAboutDisaster/Winter/

Winter.asp

http://www.nssl.noaa.gov/hazard

http://www.volcano.si.edu/

http://www-nsidc.colorado.edu

http://volcanoes.usgs.gov
appendix b – library

Version 1.0 August 2001 b-9

State Resources:

Coastal Zone Management

Emergency Management

Environmental Protection

Health

Labor

Natural Resources Management

Planning

Transportation

Local Resources:

Emergency Management

Environmental Management

Fire Department

Floodplain Management

Historical Society

Planning

Public Works Department

Non-Governmental Resources:

American Red Cross

Salvation Army

GaResourcestric Companies

Alabama Coastal Hazard Assessment

Association of Dam Safety Officials

Multi-hazard map production with GIS emphasis

National Institute of Standards and Technology

National Science Foundation

Natural Hazards Research and Applications

Information Center, University of Colorado

New Hanover County, NC Hazard Identification/Risk

Assessment

USDA, Natural Resources Conservation Service

Vulnerability Assessment Techniques and Applications

http://www.csc.noaa.gov/products/alabama/

startup.htm

http://crunch.tec.army.mil/nid/webpages/nid.cfm

http://www.esri.com/hazards

http://www.nist.gov

http://www.nsf.gov

http://www.colorado.edu/hazards

http://www.csc.noaa.gov/products/nchaz/htm/

case1.htm

http://www.nrcs.usda.gov/

http://www.csc.noaa.gov/vata/

Miscellaneous Risk Assessment Information

Click to proceed to

Appendix C

Return to

Table of Contents

Version 1.0 August 2001 c-1

appendix c

worksheets

Worksheet #1 Identify the Hazards

Worksheet #2 Profile Hazard Events

Worksheet #3a Inventory Assets (Tasks A and B)

Worksheet #3b Inventory Assets (Task C)

Worksheet #4 Estimate Losses

Worksheet #1 Identify the Hazards step 

Date: What kinds of natural hazards can affect you?

Task A. List the hazards that may occur.

1. Research newspapers and other historical records.

2. Review existing plans and reports.

3. Talk to the experts in your community, state, or region.

4. Gather information on Internet Websites.

5. Next to the hazard list below, put a check mark in the

Task A boxes beside all hazards that may occur in your

community or state.

Task B. Focus on the most prevalent hazards in your

community or state.

1. Go to hazard Websites.

2. Locate your community or state on the Website map.

3. Determine whether you are in a high-risk area. Get more

localized information if necessary.

4. Next to the hazard list below, put a check mark in the Task B

boxes beside all hazards that pose a significant threat.

Avalanche

Coastal Erosion

Coastal Storm

Dam Failure

Drought

Earthquake

Expansive Soils

Extreme Heat

Flood

Hailstorm

Hurricane

Land Subsidence

Landslide

Severe Winter Storm

Tornado

Tsunami

Volcano

Wildfire

Windstorm

Other____________

Other____________

Other____________

Note: Bolded hazards are addressed in

this How-To Guide.

Task

A

Task

B Use this space to record information you find for each of the hazards you will be

researching. Attach additional pages as necessary.

Hazard or Event Description

(type of hazard, date of event,

number of injuries, cost and

types of damage, etc.)

Source of

Information

Map

Available

for this

Hazard?

Scale of

Map

Worksheet #2 Profile Hazard Events step

Date: How Bad Can It Get?

Task A. Obtain or create a base map.

You can use existing maps from:

• Road maps

• USGS topographic maps or Digital Orthophoto

Quarter Quads (DOQQ)

• Topographic and/or planimetric maps from other

agencies

• Aerial topographic and/or planimetric maps

OR you can create

a base map using:

 •Field surveys

• GIS software

• CADD software

• Digitized paper

maps

Title of Map Scale Date

Flood

Earthquake

Tsunami

Tornado

Other

Coastal

Storm

Landslide

Wildfire

 1. Get a copy of your FIRM. ______________________________

 2. Verify the FIRM is up-to-date and complete. ________________

__________________________________________________

 1. Go to the http://geohazards.cr.usgs.gov Website.

 2. Locate your planning area on the map.

 3. Determine your PGA.

 1. Get a copy of your tsunami inundation zone map. ____________

__________________________________________________

 1. Find your design wind speed. ___________________________

__________________________________________________

 1. Get a copy of your FIRM. ______________________________

 2. Verify that the FIRM is up-to-date and complete.

__________________________________________________

 3. Determine the annual rate of coastal erosion.

__________________________________________________

 4. Find your design wind speed.

__________________________________________________

 1. Map location of previous landslides. ______________________

 2. Map the topography. __________________________________

 3. Map the geology. ____________________________________

 4. Identify the high-hazard areas on your map. ________________

 1. Map the fuel models located within the urban-wildland interface

areas. _____________________________________________

 2. Map the topography. __________________________________

 3. Determine your critical fire weather frequency. ______________

 4. Determine your fire hazard severity. ______________________

 1. Map the hazard. _____________________________________

 1. Transfer the boundaries from your FIRM onto your

base map (floodway, 100-yr flood, 500-yr flood).

 2. Transfer the BFEs onto your base map.

 1. Record your PGA: _____________________

 2. If you have more than one PGA print, download

or order your PGA map.

 1. Copy the boundary of your tsunami inundation

zone onto your base map.

 1. Record your design wind speed: _________

 2. If you have more than one design wind speed,

print, download, or copy your design wind speed

zones, copy the boundary of your design wind

speed zones on your base map, then record the

design wind speed zones on your base map.

 1. Transfer the boundaries of your coastal storm

hazard areas onto your base map.

 2. Transfer the BFEs onto your base map.

 3. Record the erosion rates on your base map:

__________________________

 4. Record the design wind speed here and on your

base map: ________________

 1. Mark the areas susceptible to landslides onto

your base map.

 1. Draw the boundaries of your wildfire hazard

areas onto your base map.

 1. Record hazard event info on your base map.

Task A. Determine the proportion of buildings, the value of buildings, and the population in your community

or state that are located in hazard areas.

Hazard _______________________________________

Worksheet #3a Inventory Assets step 

Date: What will be affected by the hazard event?

Type of

Structure

(Occupancy

Class)

Number of Structures Value of Structures Number of People

# in

Community

or State

# in

Hazard

Area

% in

Hazard

Area

$ in

Community

or State

$ in

Hazard

Area

% in

Hazard

Area

# in

Community

or State

# in

Hazard

Area

% in

Hazard

Area

Residential

Commercial

Industrial

Agricultural

Religious/

Non-profit

Government

Education

Utilities

Total

Task B. Determine whether (and where) you want to collect additional inventory data.

1. Do you know where your greatest damages may occur in your hazard areas?

2. Do you know whether your critical facilities will be operational after a hazard event?

3. Is there enough data to determine which assets are subject to the greatest potential

damages?

4. Is there enough data to determine whether significant elements of the community

are vulnerable to potential hazards?

5. Is there enough data to determine whether certain areas of historic, environmental,

political, or cultural significance are vulnerable to potential hazards?

6. Is there concern about a particular hazard because of its severity, repetitiveness, or

likelihood of occurrence?

7. Is additional data needed to justify the expenditure of community or state funds for

mitigation initiatives?

 Y N

_____ _____

_____ _____

_____ _____

_____ _____

_____ _____

_____ _____

_____ _____

page 1 of 2

Task C. Compile a detailed inventory of what can be damaged by a hazard event.

Inventory the assets (critical facilities, businesses, historic, cultural, and natural resource areas, and areas of special

consideration), that can be damaged by a hazard event.

Hazard _______________________________________

Worksheet #3b Inventory Assets step 

Date: What will be affected by the hazard event?

page 2 of 2

Name or

Description of

Asset

Sources of

Information

Size of

Building

(sq ft)

Replacement

Value

($)

Contents

Value

($)

Function

Use or

Value

($)

Displacement

Cost

($ per day)

Occupancy

or Capacity

(#)

Other

Hazard

Specific

Information

     Critical Facility Vulnerable Populations Economic Assets Special Considerations Historic/Other Considerations

Worksheet #4 Estimate Losses step 

Date: How will these hazards affect you?

Hazard _______________________________________

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