U.S. Fire Administration

TOPICAL FIRE RESEARCH SERIES

Volume 2, Issue 16

March 2002

Fires in the Wildland/Urban Interface

FINDINGS

S Development in the wildland/urban interface is growing. In the Western

U.S. alone, 38% of new home construction is adjacent to or intermixed

with the WUI.

S A dichotomy exists in dealing with WUI fires. On the one hand, environmentalists and foresters believe that a natural fire (or even a prescribed burn) is healthy for our forests. On the other hand, homeowners in these areas expect fire protection of their structures.

S WUI fires pose great challenges to the fire service. Firefighting tactics

for wildland fires differ considerable from those in structures; access to

homes and availability of water are often limited in WUI areas.

S Fire prevention programs in WUI areas are extremely important. And

homeowners must accept a measure of responsibility and be fully

aware of the risks when deciding to locate in such an environment.

Current population growth and the expanding development of North America into

traditionally nonurban areas have increasingly brought humans into contact with wildfires. Between 1985 and 1994, wildfires destroyed more than 9,000 homes in the United

States.

1 Generally, these homes were located in areas “where structures and other human

development meet or intermingle with undeveloped wildland or vegetative fuels,”2 also

known as the wildland/urban interface or intermix (WUI).

Both the definition and the development of the WUI are controversial subjects for

government officials, developers, and the fire service. By one account, nearly 38% of

new home construction in the Western United States is on properties adjacent to or intermixed with WUI.3 Nationally, the continuing development of the WUI raises serious

public policy and land use issues. Agencies at the local, state, and federal levels need to

work together to define areas as being in the WUI and then to find ways to provide services, including fire protection, to developments on these lands. Moreover, individual

communities and homeowners must be willing to accept a high degree of responsibility

for protecting their homes from wildfire.
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This report examines the socioeconomic implications of WUI fires, the unique challenges such fires pose to the fire service, and WUI fire prevention programs.

SOCIOECONOMIC EFFECTS OF WUI FIRES

Historically, WUI fires have caused significant property loss. One of the most

destructive fires occurred in October 1991 when 25 lives were lost and more than 3,000

structures were destroyed by a WUI fire in the East Bay Hills of Oakland, CA. The fire

completely overwhelmed the firefighting forces of the area and consumed nearly everything in its path.4 WUI fires are not only a problem in Western states. In the summer of

1998, wildfires destroyed nearly 500,000 acres and hundreds of structures throughout

Florida. Nearly 7,000 firefighters and military personnel from across the nation participated in the fire suppression effort, which ultimately cost between $620 and $890 million.5

FIRE SUPPRESSION IN THE WUI

Fire suppression in the WUI has become a highly controversial issue in the fire service. Some have even gone so far as to argue that it is not appropriate for publicly funded

fire suppression personnel to be required to protect homes built in a high -risk area when

those personnel can be better utilized elsewhere.6 Despite the controversy, firefighters are

still called on to fight fires in the WUI. These fires pose serious technical challenges to

the fire service.

Firefighting Tactics: On a basic level, the tactics of structural and wildland firefighting are dramatically different. A major component of structural firefighting tactics is

direct fire attack usually with water or foam. In wildland firefighting, however, personnel

generally try to extinguish a fire indirectly by starving it of fuel, usually by surrounding

it with a defensible perimeter of cleared land.

The training and equipment for structural and wildland firefighters have been

adapted to support the tactical goals mentioned above. As a result, WUI fires challenge

wildland firefighters because they are not trained in structural firefighting. By the same

token, structural firefighters have limited training in wildland fire suppression.

Jurisdiction: Since fire does not adhere to jurisdictional boundaries and WUI fires

require the expertise of both wildland and structural firefighters, firefighters from different agencies must work together to suppress fires in the WUI. This can create a variety of

issues, from command and control to payment for services rendered. Also, confusion

over jurisdictional boundaries or multijurisdictional operations can lead to reporting

issues, as it may not be clear which jurisdiction is responsible for reporting the fire or to

whom.

Access: Depending on the level of development, some areas may lack the transportation infrastructure required to allow fire department apparatus the access needed to protect homes. Roads may be too narrow or steep for fire trucks to navigate or bridges may

not be able to support the trucks’ weight.
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Water Supply: An area’s level of development and proximity to a municipal water

system will directly affect the amount of water available to firefighters for suppression

activities. Homes in areas without access to a municipal water system will be more difficult to defend and protect from wildfire, as water will have to be brought to the site in

tankers or by drawing from static water sources nearby.

WUI FIRE PREVENTION

Preventing fires costs significantly less than suppressing them. As a result, fire prevention efforts in the WUI are crucial. With this observation, it is important to understand that fire plays an important role in wildland ecosystems; some plant species even

depend on fire to propagate. For many years, however, the federal government advocated

the suppression of all wildfires, regardless of size or location. Over time, these policies

created a dangerous accumulation of vegetative fuels in our forests.

Foresters and other government officials are now struggling with how to reduce the

amount of fuel in the forests. Some favor mechanically thinning the forests through logging and other means. Others support the use of prescribed burning, where officials

deliberately set fires to clear out scrub and other brush to reduce the chance of wildfires.

Prescribed burning, however, is highly controversial. In May 2000, a prescribed burn

near Los Alamos, NM, “escaped” and caused nearly $1 billion in property loss and damage.

A Wildland/Urban Interface Fire Protection Program identified four common components of interface fires: (1) Low relative humidity, high temperatures, and high winds

often are in place before a fire starts. (2) Human activity such as arson, debris burning, or

downed electrical wires case many interface fires. (3) Many destroyed homes were

constructed with combustible material or have especially vulnerable features such as

wood shingle roofs. (4) Considerable combustible materials surround the home, such as

woodpiles and fences.

7

To highlight the importance of fire safety in the WUI, communities throughout the

country have codified requirements for homeowners to construct and maintain their

homes in a fire-safe manner. Other communities have considered tax credits for homeowners as a means to encourage fire safety in the WUI. The insurance industry also has

an important stake in protecting homes in the WUI; the Oakland Hills fires of 1991 alone

caused nearly $1.2 billion in insured property losses.

8 As such, the industry has considered adjusting premiums based on the assessed level of wildfire risk for a particular property.

Despite these measures, new homeowners in the WUI often do not understand the

risks associated with their environment and do not take the appropriate steps to protect

their homes from wildfires. Protective steps include:

S Constructing homes with fire -resistant materials.
S Situating homes on lots so as to protect them from possible fire spread.

S Clearing a perimeter of defensible space around homes.

S Installing smoke alarms.

S Developing and practicing evacuation plans in the event of a wildfire.

9

There is concern that homeowners in the WUI are receiving conflicting messages

regarding fire prevention. On one hand, most prevention programs aimed specifically

toward structure fires depict all fires as being undesirable and dangerous. However, wildfire prevention programs tend to underscore the fact that fire plays an important role in

our ecosystem and can be a valuable tool in forest fuel management.

CONCLUSIONS

As the development of the WUI continues to widen, the problem of fire in these

areas is exacerbated and the need for training, prevention, and other programs to mitigate

WUI fires is increased. Given the political, ecological, and economic implications of any

decision affecting residents and homes in the WUI, this subject is likely to remain controversial for the foreseeable future.

For further information on fires in the WUI, contact the National Wildland/Urban

Interface Fire Protection Program (http://www.firewise.org). Additional information is

also available on the USFA website at http://www.usfa.fema.gov/wildfire/. If you live in

the WUI and are seeking specific information about fire protection in your area, contact

your local fire department.

NOTES:

1. The Wildland/Urban Fire Hazard, Insurances Services Office, Inc., December 1997.

(http://www.iso.com/docs/stud009.htm, January 8, 2002)

2. Federal Wildland Fire Policy, U.S. Department of Agriculture Forest Service, Chartered 1994, Revised

2001. (http://www.fs.fed.us/land/wdfire7c.htm, January 4, 2002)

3. Wildland Fire Preparedness/Education Partnership, Firewise Colorado, February 2001.

4. The East Bay Hills Fire Oakland–Berkeley, California (October 19–22), Technical Report Series, U.S.

Fire Administration, Federal Emergency Management Agency.

5. Grace, Sue and Wade, Dale, Ecological and Economic Consequences of the 1998 Florida Wildfires,

Florida Department of Forestry, 2000.

6. Sampson, Neil, “Living With Nature: Are We Willing To Pay The Price?” Wildfire News & Notes,

1996

7. The Wildland/Urban Fire Hazard, op. cit.

8. Fire in the United States: 1985–1994, Ninth Edition, U.S. Fire Administration, Federal Emergency

Management Agency, p. 195.

9. Protecting Your Home From Wildfire, National Wildland/Urban Interface Fire Protection Program.

(http://www.firewise.org/pubs/protect/step1.html, December 27, 2001)

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