NIST Special Publication 1139

Progress Report, National Institute of 

Standards and Technology (NIST)

Technical Investigation of the May 22, 

2011, Tornado in Joplin, Missouri

Erica D. Kuligowski

Franklin T. Lombardo

Long T. Phan

Marc L. Levitan

David P. Jorgensen 

http://dx.doi.org/10.6028/NIST.SP.1139

NIST Special Publication 1139 

Progress Report, National Institute of 

Standards and Technology (NIST)

Technical Investigation of the May 22, 

2011, Tornado in Joplin, Missouri

Erica D. Kuligowski

Franklin T. Lombardo

Long T. Phan

Marc L. Levitan

Engineering Laboratory

David P. Jorgensen 

Warning R&D Division

National Severe Storms Laboratory

National Oceanic and Atmospheric Administration

http://dx.doi.org/10.6028/NIST.SP.1139

November 2012

U.S. Department of Commerce 

Rebecca Blank, Acting Secretary

National Institute of Standards and Technology 

Patrick D. Gallagher, Under Secretary of Commerce for Standards and Technology and Director 
Disclaimer No. 1

Certain commercial entities, equipment, or materials may be identified in this

document in order to describe an experimental procedure or concept adequately.

Such identification is not intended to imply recommendation or endorsement by the

National Institute of Standards and Technology, nor is it intended to imply that the

entities, materials, or equipment are necessarily the best available for the purpose. 

Disclaimer No. 2

NIST takes no position as to whether the design or construction of any building 

discussed in this report was compliant with any code since, due to the destruction 

of the buildings, NIST could not verify the actual (or as-built) construction, the 

properties and condition of the materials used, or changes to the original construction made over the life of the buildings. In addition, NIST could not verify the interpretations of codes used by applicable authorities in determining compliance 

when implementing building codes.

Use in Legal Proceedings

No part of any report resulting from a NIST investigation into a structural failure 

or from an investigation under the National Construction Safety Team Act may be 

used in any suit or action for damages arising out of any matter mentioned in such 

report (15 U.S.C. 281a, as amended).

National Institute of Standards and Technology Special Publication 1139

Natl. Inst. Stand. Technol. Spec. Publ. 1139, 25 pages (November 2012) 

http://dx.doi.org/10.6028/NIST.SP.1139

CODEN: NSPUE2
NIST Progress Report—Investigation of Joplin Tornado—November 2012 iii

Table of Contents

List of Acronyms, Abbreviations, and Conversion Factors............................................................ v

Summary....................................................................................................................................... vii

Chapter 1. Introduction .................................................................................................................. 1

1.1 Goals of the Joplin Tornado Investigation....................................................................... 1

1.2 Objectives of the Joplin Tornado Investigation............................................................... 1

1.3 Authorities and Use of Information in Legal Proceedings .............................................. 2

1.4 Liaison with the Professional Community, the Public, and Local Authorities................ 2

Chapter 2. Implementation of Legislative Authorities .................................................................. 3

2.1 Establishment of National Construction Safety Team..................................................... 3

2.2 NCST Advisory Committee............................................................................................. 3

Chapter 3. Progress on Joplin Tornado Investigation.................................................................... 5

3.1 Technical Approach of Investigation and Scope of Progress Report .............................. 5

3.2 Status of Data Collection Efforts..................................................................................... 6

3.3 Tornado Hazard Characteristics....................................................................................... 9

3.4 Emergency Communications, Public Response, Fatalities and Injuries........................ 14

3.5 Response of Buildings, Including Designated Safe Areas............................................. 19

3.6 Performance of Lifelines Related to Continuity of Operations of Buildings ................ 23

3.7 Identification of Codes, Standards, and Practices That Warrant Revision.................... 25

3.8 Moving Forward ............................................................................................................ 25
iv NIST Progress Report—Investigation of Joplin Tornado—November 2012

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NIST Progress Report—Investigation of Joplin Tornado—November 2012 v

List of Acronyms, Abbreviations, and Conversion Factors

Acronyms

ADA Americans with Disabilities Act of 1990

ANSI American National Standards Institute

ASCE American Society of Civil Engineers

BOCA Building Officials and Code Administrators

BTS box-type system

CDT central daylight time

CF concrete frame

CMU concrete masonry unit

EF Enhanced Fujita

FEMA Federal Emergency Management Agency

GIS geographic information system

IBC International Building Code

ICC International Code Council

IEC International Electrotechnical Commission

ISO International Organization for Standardization

NCST National Construction Safety Team

NFIRS National Fire Incident Reporting System

NFPA National Fire Protection Association

NIST National Institute of Standards and Technology

NOAA National Oceanic and Atmospheric Administration

NWS National Weather Service

SF steel frame

SPC Storm Prediction Center (NOAA)

UL Underwriters Laboratories

USC United States Code

WF wood frame

Abbreviations and Conversion Factors

deg wind direction in degrees mph mile(s) per hour

ft foot, feet s second(s)

km kilometer(s)

m meter(s), 1 m = 3.281 ft

m/s meter(s) per second, 0.447 m/s = 1 mph
vi NIST Progress Report—Investigation of Joplin Tornado—November 2012

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NIST Progress Report—Investigation of Joplin Tornado—November 2012 vii

Summary

Following a preliminary reconnaissance that began on May 24, 2011, the National Institute of 

Standards and Technology (NIST) announced on June 29, 2011, that it would conduct a technical 

investigation of the tornado that struck Joplin, MO, on May 22, 2011. In November 2011, NIST 

released a draft plan for the study and briefed the National Construction Safety Team (NCST) 

Advisory Committee on the progress of the investigation in a meeting that was open to the public. The final investigation plan, released in May 2012, can be found at http://www.nist.gov/

manuscript-publication-search.cfm?pub_id=911000.

This report summarizes the progress NIST has made and the cooperation it has received from a 

variety of organizations in conducting the study. It includes updates on the following activities:

• Establishing the investigative Team under the NCST Act

• Briefing the NCST Advisory Committee

• Identifying and collecting materials relevant to the investigation from State and local 

government agencies, businesses, and other sources

• Determining the tornado hazard characteristics, including the meteorological conditions 

leading to and during the event, the tornadic wind field, and the tornado climatology

• Investigating the behavior and fate of individuals—both those who survived and those 

who did not—by collecting and analyzing information on injuries and fatalities, human 

behavior, situational awareness, and emergency communications before and during the 

tornado

• Analyzing the performance of single- and multi-family residential buildings, commercial

structures, and critical buildings, including designated safe areas

• Assessing the performance of lifelines as it relates to the continuity of operations of residential, commercial, and critical buildings

Highlights of this progress report include the following:

• A timeline of meteorological events and emergency communications preceding and during the tornado, including warnings and siren soundings

• The outline of an approach for fitting a tornadic wind field model to the observed data to 

create a map estimating maximum surface wind speeds in the tornado

• Information about first-person data collection efforts targeting human behavior, situational awareness, and emergency communications before and during the tornado, including a 

description of the data collection and analysis methodology

• Analysis of information relevant to the design, construction, and performance of buildings during the tornado
viii NIST Progress Report—Investigation of Joplin Tornado—November 2012

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NIST Progress Report—Investigation of Joplin Tornado—November 2012 1

Chapter 1. Introduction

This report summarizes the progress made by the National Institute of Standards and Technology 

(NIST) in its technical investigation of the tornado that struck Joplin, MO, on May 22, 2011 (referred to after this point as “the Joplin tornado”).

1.1 Goals of the Joplin Tornado Investigation 

NIST’s study of the Joplin tornado has two major goals. The first is to investigate the wind environment and technical conditions that caused fatalities and injuries; the performance of emergency communications systems and the public response to such communications; and the 

performance of residential, commercial, and critical buildings, designated safe areas in buildings, 

and lifelines. The second goal is to develop findings and recommendations that can serve as the 

basis for

• potential improvements to requirements for the design and construction of buildings, designated safe areas, and lifeline facilities in tornado-prone regions;

• potential improvements to guidance for tornado warning systems and emergency response procedures;

• potential revisions to building, fire, and emergency communications codes, standards, 

and practices; and 

• potential improvements to public safety.

1.2 Objectives of the Joplin Tornado Investigation

The primary objectives of the NIST technical investigation of the Joplin tornado are to:

1. Determine the tornado hazard characteristics and associated wind fields in the context of 

historical data

2. Determine the pattern, location, and cause of fatalities and injuries, and associated performance of emergency communications systems and public response

3. Determine the response of residential, commercial, and critical buildings, including the 

performance of designated safe areas

4. Determine the performance of lifelines as it relates to the continuity of operations of residential, commercial, and critical buildings

5. Identify, as specifically as possible, areas in current building, fire, and emergency communications codes, standards, and practices that warrant revision
2 NIST Progress Report—Investigation of Joplin Tornado—November 2012

1.3 Authorities and Use of Information in Legal Proceedings 

NIST is a non-regulatory agency of the U.S. Department of Commerce. NIST investigations are 

focused on fact finding, not fault finding. No part of any report resulting from a NIST investigation into a structural failure or from an investigation under the National Construction Safety 

Team (NCST) Act may be used in any suit or action for damages arising out of any matter mentioned in such report (15 U.S.C. 281a, as amended by Public Law 107–231).

1.4 Liaison with the Professional Community, the Public, and Local Authorities 

NIST is maintaining ongoing liaison with the professional community, the general public, and

local authorities during the investigation through briefings and presentations. NIST has established the following website to communicate information related to the investigation: 

http://www.nist.gov/el/disasterstudies/weather/joplin_tornado_2011.cfm. This information also 

is available in print; every effort will be made to ensure that those without internet access can 

receive the same information by mail.

Communications may be sent to NIST via electronic mail (e-mail), facsimile, or regular mail:

E-mail: disaster@nist.gov

Facsimile: (301) 975–4032

Regular mail: Disaster and Failure Studies Program

Engineering Laboratory

National Institute of Standards and Technology

100 Bureau Drive Stop 8611

Gaithersburg, MD 20899–8611
NIST Progress Report—Investigation of Joplin Tornado—November 2012 3

Chapter 2. Implementation of Legislative Authorities

2.1 Establishment of National Construction Safety Team

Following the May 22, 2011, tornado that devastated the city of Joplin, MO, NIST sent four engineers to Missouri from May 24 through May 28 to conduct a preliminary reconnaissance.

1

Based on analysis of the data collected and other criteria required by law and regulation, NIST 

Director Patrick Gallagher established a Team under the NCST Act on June 29, 2011, to proceed 

with a more comprehensive study of the impacts of the disaster. The establishment of the Team 

was announced in the Federal Register on July 19, 2011 (76 FR 42683). Additional information 

regarding the rationale for the technical investigation is provided in the investigation plan 

(http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911000).

2.2 NCST Advisory Committee 

The NCST Advisory Committee was provided an update on the Joplin tornado study at its November 7, 2011, meeting in Gaithersburg, MD. The committee was briefed on the draft investigation plan and the research progress to date. A copy of this presentation is available at 

http://www.nist.gov/el/disasterstudies/ncst/upload/NCSTACJoplin110411.pdf. Approximately

one-half hour was reserved for public comments, and speaking times were assigned on a firstcome, first-served basis as described in the Federal Register notice announcing the meeting (76 

FR 64326, October 18, 2011).

Additional information about the NCST Act and the NCST Advisory Committee is available at 

http://www.nist.gov/el/disasterstudies/ncst/.

 1 See http://www.nist.gov/el/disasterstudies/upload/Joplin_Reconnaissance_Presentation061511-2.pdf for more information about the NIST preliminary reconnaissance at the site of the Joplin tornado.
4 NIST Progress Report—Investigation of Joplin Tornado—November 2012

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NIST Progress Report—Investigation of Joplin Tornado—November 2012 5

Chapter 3. Progress on Joplin Tornado Investigation

3.1 Technical Approach of Investigation and Scope of Progress Report 

The technical approach of the Joplin tornado investigation, described in the final investigation 

plan (http://www.nist.gov/manuscript-publication-search.cfm?pub_id=911000) released in May 

2012, includes the following major tasks:

• Identify Issues Requiring Technical Study

Review data and information collected through the NIST preliminary reconnaissance related to the following: the performance of both the building envelope and the building’s 

main wind force resistance system in residential (e.g., single-family and multi-family 

wood frame), commercial (e.g., professional office, big box retail), and critical or high 

occupancy (e.g., hospital, school) buildings; the wind conditions based on observed damage and available measurements; the performance of designated safe areas and lifeline facilities; the tornado warning systems and emergency procedures, and the patterns, 

locations, and causes of fatalities and injuries; and the locations and causes of posttornado fires.

• Collect Data

Gather the following types of data and information: building design documents, records, 

plans, and specifications; building construction, maintenance, and operations records; 

video and photographic data; field data; interviews and other oral and written accounts 

from building occupants, families of victims, emergency responders, building operators, 

and other witnesses; emergency response records, including audio communications; 

physical evidence; and other records. Obtain these materials from building, fire, and 

emergency response officials; Federal, State, and local authorities; and the public. To the 

extent permitted by law and policy, collected data will be stored in NIST’s publicly accessible Disaster and Failure Events Data Repository. 

• Analyze and Compare Designs, Codes, and Practices for Buildings and Emergency 

Communications Systems

Analyze and compare the codes, standards, and specifications used at the time of the tornado and before for the City of Joplin; compare as-designed conditions with model code 

requirements and with as-built conditions observed in the NIST preliminary reconnaissance; and review and analyze practices used to design, construct, and operate buildings 

and emergency communications systems. 

• Prepare Technical Findings and Recommendations

Prepare final reports, incorporating established review processes involving the NIST Editorial Review Board; augmented reviews conducted by NIST senior management, legal

counsel, and public affairs personnel; reviews of key reports by the NCST Advisory 

Committee; and, as necessary, reviews of key reports by individual outside experts. 

• Identify Needs for Revisions to Codes, Standards, and Practices

Identify specific areas of codes, standards, and practices in need of revision based on the 

findings of the investigation.
6 NIST Progress Report—Investigation of Joplin Tornado—November 2012

These main tasks encompass a number of more specific tasks that are organized around the five 

objectives of the study listed in Chapter 1. Descriptions of these objective-specific tasks and the 

overall technical approach are available in the investigation plan (see http://www.nist.gov/

manuscript-publication-search.cfm?pub_id=911000, Attachment 1). Table 1 summarizes, for 

each objective of the investigation, the subjects that are under study and the purpose of the specific tasks that are being performed.

Table 1. Technical investigation of the Joplin tornado

Study

objectivea

Subject(s)

being studied Purpose of associated tasks

1 Tornado Hazard 

Characteristics

To obtain, review, and analyze information and documents relating to the specific characteristics of the Joplin tornado and 

how those characteristics compare to similar tornado events in 

a historical context at the local, regional, and national levels.

2 Emergency Communications, Public Response, Fatalities and 

Injuries

To investigate the behavior and fate of individuals—both those 

who survived and those who did not—by collecting and analyzing information on injuries and fatalities and on human behavior, situational awareness, and emergency communications 

before and during the Joplin tornado.

3 Response of Buildings, Including Designated Safe AreasTo obtain, review, and analyze information and documents relating to the design, construction, and performance of singleand multi-family residential structures and of commercial and 

critical buildings, including designated safe areas, affected by 

the Joplin tornado, and to identify technical issues for development and/or revisions of codes, standards, and practices 

pertaining to designing for tornadoes.

4 Performance of Lifelines Related to Continuity of Operations 

of Buildings

To obtain, review, and analyze information and documents relating to the performance of lifelines that support continuity of 

operations for selected buildings and facilities affected by the 

Joplin tornado.

5 Identification of 

Codes, Standards,

and Practices That 

Warrant Revision

To make recommendations for potential improvements to 

model codes, standards, and practices, and/or for further research based on findings from this investigation of the Joplin 

tornado.

a Objectives 1–5 are defined in Chapter 1.

This report summarizes the progress made by NIST and the cooperation it has received from a 

variety of organizations. It covers the status of data collection efforts and progress toward meeting the five objectives of the investigation.

3.2 Status of Data Collection Efforts 

NIST is basing its review, analysis, and modeling work for the Joplin tornado investigation on a

solid foundation of technical evidence. NIST has obtained critical data such as building docu-
NIST Progress Report—Investigation of Joplin Tornado—November 2012 7

ments, video and photographic records, emergency response records, and oral histories. NIST 

has received considerable cooperation and information from a variety of businesses, organizations, professional associations, and individuals representing building designers, building owners, utilities, disaster researchers, and disaster responders. NIST has also received considerable 

cooperation and information from citizens in the Joplin area, as well as from Federal, State, and 

local authorities.

Local authorities providing information include the Joplin Public Works Department, the Joplin 

Police Department, the Joplin Fire Department, Joplin Schools, and the Joplin/Jasper County 

Emergency Management Agency. State authorities providing information include the Missouri 

Department of Public Safety’s State Emergency Management Agency, the Missouri Department 

of Health and Senior Services, the Missouri State Highway Patrol, the Missouri Division of Fire 

Safety, the Oklahoma State Department of Health, and the Kansas Department of Health and Environment’s Office of Vital Statistics. Federal authorities providing information include the U.S. 

Army Corps of Engineers, the Federal Emergency Management Agency (FEMA), the National 

Oceanic and Atmospheric Administration’s National Weather Service (NWS), and the U.S. Department of Health and Human Services’ Centers for Disease Control and Prevention.

NIST has also received information from the American Red Cross; Mercy (the parent organization for St. John’s Regional Medical Center); architectural and engineering design firms Patterson Latimer Jones Brannon Denham (PLJBD) Inc. and Heery International, Inc.; the Structural 

Engineers Association of Kansas and Missouri; the Missouri Structural Assessment and Visual 

Evaluation (SAVE) Coalition; the Empire District Electric Company; and GeoEye, Inc.

The documents and other information obtained relate to meteorological conditions, warning 

communication systems, warnings issued, emergency response activities, the design and construction of buildings, the performance of buildings and lifelines, and fatalities and injuries. 

They include information such as the following:

• Meteorological data and records for the Joplin area on May 22, 2011

• Emergency management and hazard mitigation plans

• A tornado siren operations plan and coverage map

• Warning information provided to the public on May 22, 2011

• Audio recordings of emergency responder radio traffic

• Audio recordings of 911 calls

• Fatality and injury records and information

• Interviews with survivors and with friends and families of deceased victims

• Plans and specifications for a number of buildings in the tornado impacted area

• Local building and fire code adoptions, legislation, and ordinances

• Photographs and videos made during and after the tornado
8 NIST Progress Report—Investigation of Joplin Tornado—November 2012

• Pre- and post-tornado aerial imagery

• Building damage reports

• A building/property information database and associated geographic information system 

(GIS) files

• A building damage database and GIS files

• A sign damage database and photographs

NIST has not been able to locate the following important documents and materials:

• Design information for the original seven-story hospital building (West Tower) at St. 

John’s Regional Medical Center, including architectural and structural plans and window 

product information

• Design information for renovations to the West Tower at St. John’s Regional Medical 

Center that involved modification or replacement of windows, particularly the 1969 renovations to the Behavioral Health Unit

The Joplin Public Works Department has informed NIST that some of their records were lost to 

water damage. They were only able to provide drawing sets for some of the requested buildings, 

including some of the drawings sought for St. John’s Regional Medical Center. Additional partial drawing sets for some of the buildings at St. John’s Regional Medical Center were obtained 

from Mercy and from the architectural and engineering design firm Heery International, Inc. 

NIST is working with the Missouri Department of Health and Senior Services to obtain additional information about those who were injured. NIST recently obtained a list of mutual aid fire 

departments that responded to the tornado from the Office of the State Fire Marshal, and has 

contacted these departments to request any records they may have pertaining to these fires.

NIST has also obtained and reviewed publications from other studies of various aspects of the 

May 22, 2011, tornado in Joplin. They include the publications cited below:

• “NWS Central Region Service Assessment: Joplin, Missouri, Tornado—May 22, 2011,”

National Weather Service, Central Region Headquarters, Kansas City, MO, July 2011.

• “Mitigation Assessment Team Report—Spring 2011 Tornadoes: April 25–28 and May 

22, Building Performance Observations, Recommendations, and Technical Guidance,”

FEMA P–908, Federal Emergency Management Agency, Washington, DC, May 2012.

• Joplin Tornado Committee, “Investigations and Recommendations Based on the May 22, 

2011 Joplin, Missouri Tornado,” Structural Engineers Association of Kansas and Missouri, Shawnee Mission, KS, May 2012.

• Natural Disaster Task Force, “Analysis of Damage from Historic Tornado in Joplin, Missouri, U.S.A. on May 22, 2011,” Report 201–12–01, Tilt-Up Concrete Association, 

Mount Vernon, IA, January 2012.
NIST Progress Report—Investigation of Joplin Tornado—November 2012 9

• D. O. Prevatt, W. Coulbourne, A. J. Graettinger, S. Pei, R. Gupta, and D. Grau, “Joplin 

Tornado of 2011: Damage Survey and Case for Tornado-Resilient Codes,” American Society of Civil Engineers (in press).

• B. K. Paul and M. Stimers, “Tornado Warnings and Tornado Fatalities: The Case of May 

22, 2011 Tornado in Joplin, Missouri,” Quick Response Report QR226, University of 

Colorado at Boulder, Natural Hazards Center, Boulder, CO, 2011.

• K. M. Simmons and D. Sutter, “Deadly Season: Analysis of the 2011 Tornado Outbreaks,” American Meteorological Society, Boston (2012).

• M. Smith, “When the Sirens Were Silent: How the Warning System Failed a Community,” Mennonite Press, Newton, KS (2012).

NIST’s evidence collection is nearly complete. Additional records on injuries and on fires following the tornado have been requested from the Missouri Department of Health and Senior Services and the many area fire departments providing mutual aid to Joplin, respectively. Despite 

significant efforts, NIST has been unable to locate the design information for the original sevenstory hospital building at St. John’s Regional Medical Center and later renovations to exterior 

windows, as identified in this section. NIST seeks information from the public identifying potential sources of these documents. 

3.3 Tornado Hazard Characteristics

This section describes the progress that NIST has made in carrying out the tasks specifically related to study Objective 1 (Determine the tornado hazard characteristics and associated wind 

fields in the context of historical data).

Task 1.1: Collect data on meteorological conditions related to the Joplin tornado; pre-storm and 

post-storm conditions and damage; and historical and climatological information on tornadoes 

and impacts in the Joplin area.

Data collected to support Objective 1 include wind and meteorological data, photographs, videos, and GIS-based data sets. A summary of the data is shown in Table 2. 

Task 1.2: Assess meteorological conditions leading to and during the tornado, including timeline.

Investigation of surface and upper-air charts in addition to large-scale environmental parameters 

identified a situation favorable for severe thunderstorm and tornado development. This situation 

was reflected by convective outlooks and tornado watches issued by the NOAA Storm Prediction 

Center (SPC), which has nationwide responsibility for issuing tornado and thunderstorm watches

during the periods leading up to such events.

Once thunderstorms developed, tornado warnings were issued in the Joplin area by the local 

NWS office (NWS/Springfield, MO) based on NWS radar imagery, which showed echoes with 

characteristics of possible tornadic thunderstorms to the west of Joplin. Based on this information, NIST constructed a timeline of the tornado-related events on May 22, 2011. This 
10 NIST Progress Report—Investigation of Joplin Tornado—November 2012

Table 2. Data collected in support of investigation Objective 1

Data type Data list

Meteorological/

Wind

Joplin Airport meteorological/wind data, WSR–88D radar data, National 

Oceanic and Atmospheric Administration (NOAA) graphics and text, Wind 

Profiler and Model Sounding data, other meteorological data, NOAA tornado database

Photographs Building and infrastructure damage, street sign damage

Videos Surveillance and other videos made during the tornado, videos of posttornado damage

GIS Based Post-storm aerial photos, tornado path, local roads/boundaries, structural 

damage databases, tax assessor data, NIST created (e.g., tree fall), fatality 

locations

Miscellaneous Street sign damage database, lifeline information 

timeline, shown in Fig. 1, includes outlooks and watches issued by the SPC, warnings issued by 

NWS/Springfield, locations of the tornado estimated from surveillance videos, and sirens activated by the Joplin/Jasper County Emergency Management Agency.

Figure 1. Timeline of meteorological events, warnings, and siren soundings (central daylight 

time (CDT))

Tornado affects 

Joplin East 

Middle School

Tornado 

affects 

Joplin 

High 

School

Second 3-minute 

siren sounded as 

tornado enters the 

City of Joplin

Initial tornado 

touchdown 

(Spotter reports)

Second tornado 

warning issued

Initial 3-minute 

siren sounded

First tornado 

warning issued

Moderate risk of 

severe storms issued 

by SPC

Tornado watch 

issued by SPC

5:50

5:30

5:10

4:00

3:00

2:00

5:20

5:40

1:30 pm

3:00 pm

5:09 pm

5:11 pm

5:17 pm 5:34 pm

5:38 pm

5:42 pm

5:48 pm

May 22, 2011

Watches and warnings timeline

Tornado timeline

Siren timeline
NIST Progress Report—Investigation of Joplin Tornado—November 2012 11

Task 1.3: Develop wind speed estimates for the tornado.

As radar information did not provide details on near-surface (less than 20 m above ground) wind 

speeds where most damage occurred, both direct and indirect methods were used to quantify the 

near-surface wind environment for the Joplin tornado. Wind speeds were measured at the Joplin 

Airport Automated Surface Observing Station (call letters KJLN). Although the station is located 8–10 km (5–6 miles) north of the most significant tornado damage, wind speeds there appear 

to have been influenced by the tornado (Fig. 2). The shaded area in Fig. 2 (5:34 p.m. CDT to 

5:48 p.m. CDT) represents the approximate period when the tornado was on the ground and 

causing damage in the Joplin area. Around this time, wind gusts increased to near 24 m/s (54

mph), 2-minute mean wind speeds approached 20 m/s (45 mph), and the mean wind direction 

was consistent with the position of the tornado. 

Figure 2. Joplin Airport Automated Surface Observing Station (KJLN) time history of mean and 

gust wind speed and mean wind direction from 5 p.m. to 6 p.m. CDT, May 22, 2011. (Data 

source: National Climatic Data Center)

Since the wind speeds measured at KJLN did not include those that produced significant damage, indirect methods of estimating wind speeds are also being used for this task, including inferring wind speeds based on observed damage using the Enhanced Fujita (EF) Scale and 

modeling the wind field using a Rankine vortex model fitted to tree fall patterns. The procedures 

being used for each of these methods are summarized below.

EF-Scale Estimation:

• Selected structures surveyed by NIST (for investigation Objective 3) were assigned EFScale ratings based on ground surveillance and post-storm aerial photographs.

0

10

20

30

40

50

60

Wind Speed (mph)

Time (CDT)

5:00 PM 5:15 PM 5:30 PM 5:45 PM 6:00 PM

Wind Direction (deg)

0

60

120

180

240

300

360

3-s Wind Gust (mph)

2-min Wind Speed (mph)

Wind Direction (deg)
12 NIST Progress Report—Investigation of Joplin Tornado—November 2012

• Approximately 7500 residential structures were damaged or destroyed by the Joplin tornado. A database provided by Jasper County Geographic Information Systems categorized the damage by “type” (e.g., light, medium, heavy/totaled, demolished). As part of 

the investigation, NIST has developed a methodology to compare these general damage 

types with damage and wind speed information contained in the EF Scale.

Wind Field/Tree Fall Model:

• A computer-based “grid” was developed and overlaid on a map of Joplin, marking points

32 m (106 ft) apart latitudinally and longitudinally throughout the city. The grid points 

represent the locations of modeled trees and where the wind velocity is calculated based 

on the Rankine vortex model. 

• Initial parameters (i.e., initial inputs) for the Rankine vortex model were estimated using

Joplin-specific information on tornado translation speed and direction from radar data

and surveillance videos, the tornado’s touchdown location and radius of maximum wind 

from post-storm aerial imagery, and critical tree fall wind speed from storm reports and 

tree experts. Other parameters in the model were initialized using consensus information 

from peer-reviewed tornado studies. Supplementary information from survivor interviews (investigation Objective 2) was also utilized.

• Given the initialization parameters, the wind field was translated through the grid system. 

At each time step (approximately every 1.2 s), a wind speed and direction were estimated 

at each grid point using the parameters of the Rankine vortex model. Once the wind 

speed at a grid point exceeded the critical tree fall wind speed, the tree was assumed to 

fall along the wind direction corresponding to that wind speed. 

• The modeled tree fall output, which included information on the direction of tree fall as 

well as tree damage dimensions (e.g., damage width), was then compared to observed 

tree fall directions and dimensions estimated from post-storm aerial photographs. Parameters in the Rankine vortex model were modified until a resemblance between modeled 

and observed tree fall was achieved. These parameters are being used to create overall 

wind field (wind speed, wind direction, time) information for locations throughout Joplin, 

including specific structures surveyed by NIST pursuant to study Objective 3.

Task 1.4: Assess the Joplin tornado in a climatological context, including probabilistic approaches used to assess tornado hazards at local, regional, and national levels.

A literature review of previous U.S. tornado climatology studies was performed. Information on 

current tornado wind speed mapping and design guidance in the United States was obtained and 

reviewed, including the following standards and guidelines for nuclear facilities, storm shelters,

and safe rooms:

• ANSI/ANS–2.3–2011, Standard for Estimating Tornado, Hurricane and Extreme Straight 

Line Wind Characteristics at Nuclear Facility Sites (2011)

• ASCE/SEI 7–10, Minimum Design Loads for Buildings and Other Structures (2010)

• ICC 500–2008, Standard for the Design and Construction of Storm Shelters (2008)
NIST Progress Report—Investigation of Joplin Tornado—November 2012 13

• FEMA 361, Design and Construction Guidance for Community Safe Rooms (2008)

The official tornado database (1950–2011) published by NOAA was used to assess a baseline 

U.S. tornado climatology for this investigation. Due to a number of inconsistencies in the database for the lower intensity tornadoes, a probabilistic analysis was performed on only EF2 and

higher tornadoes. Figure 3 shows a density estimation of EF2 and higher tornado touchdown 

locations in the contiguous United States. Touchdown locations are denoted by black dots. Over 

11,000 tornadoes classified as EF2 or greater have been rated and recorded in the United States

since 1950. Probabilistic estimations are being developed for EF2 through EF5 tornadoes both 

separately and in combination. These estimations include calibrations and assessments of the 

tornado hazard at local, regional, and national levels and will be compared to current tornado and 

wind-load design guidance. 

Figure 3. Density estimation of EF2+ tornadoes during the period 1950–2011. Black dots represent individual touchdown locations. The contour lines denote gradations in the density of occurrence, from higher (areas enclosed by red and orange) to lower (areas encircled by greens 

and blues). (Data source: NOAA/SPC)

Task 1.5: Analyze the spatial characteristics and consequences of the Joplin tornado, including 

the historical context.

This task involves significant input from Tasks 1.2 through 1.4, above, as well as from the work 

being done for investigation Objectives 2, 3, and 4. Work on this task is performed as results 

from the other parts of the investigation become available.

 120 °

 W 

 110°

 W 100°

 W 90°

 W 

 80°

 W 

 70°

 W 

 30°

 N 

 40°

 N 

 50°

 N 
14 NIST Progress Report—Investigation of Joplin Tornado—November 2012

Task 1.6: Assess the practice of rating tornadoes based on observed damage, using the Enhanced Fujita (EF) Scale.

NIST has developed a brief history of the EF Scale and its predecessor, the F Scale, for this investigation. Official guidance regarding the implementation and use of the EF Scale, especially 

guidance concerning significant tornadoes (EF3 or greater) has been researched to determine 

possible methods of enhancing the rating process. To compare official guidance about the EF 

Scale to its use in practice, studies and findings regarding use of the scale, including those pertaining to the Joplin tornado and other recent, violent tornado events (e.g., Greensburg, KS, Tuscaloosa, AL) are being compared, and observations relating to the appropriateness and 

sufficiency of indicators used for damage are being explored. 

3.4 Emergency Communications, Public Response, Fatalities and Injuries

In order to investigate the behavior and fate of individuals—both those who survived and those 

who did not—data are being collected and analyzed in the areas of human behavior, situational

awareness, and emergency communications before and during the Joplin tornado, and in relation 

to injuries and fatalities.

Task 2.1: Gather baseline information on the response of individuals to the Joplin tornado.

NIST is collecting data on the response of individuals to the Joplin tornado from a number of 

sources. First, interviews were conducted via telephone or face-to-face meetings with survivors 

and with the friends and families of deceased victims. Interviewees were recruited by means of a 

NIST Tech Beat article that was posted on the NIST website,2 flyers, and Joplin area newspaper 

and radio coverage. Also, the City of Joplin’s public information officer and emergency manager, and members of the Joplin Area Chamber of Commerce and local faith-based organizations

assisted NIST in publicizing the project. This very visible public recruitment enabled NIST to 

interview willing participants from a variety of geographic locations throughout the Joplin area, 

including some who had been displaced by the storm. Individuals interested in telling their stories were pre-interviewed to ensure that they in fact were located (or knew of someone who was 

located) in or near the damage path during the tornado.

After careful consideration, NIST determined that a semi-structured interviewing technique best 

fit the requirements of this investigation. Highly structured interviews use a fixed set of questions, often with set response options that allow for ease of data comparison from one interview 

to the next, while unstructured interviews are conducted more like a conversation between the 

interviewee and interviewer, where very little structure is provided by a question set. The semistructured interviewing technique allows for both the collection of rich, detailed data on tornado

experiences, as well as the opportunity for comparison among similar data.

Following this semi-structured approach, interviews were conducted in two phases. In phase 1, 

respondents were asked to describe their experiences from the time they first became aware that 

something was happening until the moment they responded to the tornado. Phase 2 was more 

 2 http://www.nist.gov/el/disasterstudies/joplin-101311.cfm.
NIST Progress Report—Investigation of Joplin Tornado—November 2012 15

structured; the interviewer asked follow-up or clarifying questions about important topics from a 

pre-established list of probing questions. The list of questions was developed by collecting and 

analyzing over 100 media accounts of Joplin tornado eyewitness survivor stories and probed the 

following topics: awareness of the event, emergency communications received, actions taken, 

risk perceptions, pre-existing or event-driven injuries or impairments, previous experiences with 

severe storms, and familiarity with and perspectives on the emergency communications system 

in Joplin. At the end of the interview, interviewees were also asked to help recruit other individuals, such as friends, family members, or coworkers, who might be interested in participating in 

the investigation. 

For 5 days immediately following the tornado and then again from October 2011 through February 2012, NIST interviewed 165 survivors of the tornado, in a combination of in-person and telephone interviews.

3 These 165 individuals represent a convenience sample of survivors, since 

interviews were performed with persons who volunteered to participate or were suggested to 

NIST by those who volunteered (known as the snowball sampling technique). NIST determined 

that interviewing was complete when two requirements were met. The first was that certain topics (i.e., experiences with the tornado on May 22, options for protective action, and previous experiences with and perspectives on warning systems and tornadoes) were saturated, in that very 

little new information was being collected as the interviews continued. The second was that the 

convenience sample varied by age, geographic location throughout the damage path (i.e., address), and physical location during the event (i.e., home, business, outdoors, or vehicle).

The respondents ranged in age from 19 to 88, with a mean age of 51. Gender was also distributed, with women making up 60 percent of the sample. A geographic analysis of the locations of 

respondents showed that the sample was well distributed across the tornado path through Joplin. 

Reported physical locations of the interviewees at the time of tornado touchdown were also 

widely distributed: approximately 68 percent were at their or someone else’s home (or apartment), 13 percent were in a private business, 7 percent were driving or stopped in a vehicle, 5 

percent were in St. John’s Regional Medical Center, 5 percent were in a Joplin area church, and 

the remaining 2 percent of the sample were either located outside of buildings or did not specifically state where they were located as the storm struck. Respondents located at home took protection in various places, including tornado shelters, full or partial basements, crawl spaces, the 

first floors of apartment complexes or duplexes, and internal locations within homes, such as 

bathrooms, closets, or hallways.

A portion of the survivor interviews (8 percent) were conducted with managers and employees of 

local businesses and institutions, as well as individuals with authoritative roles at St. John’s Regional Medical Center. These individuals often had others’ safety in mind, in addition to their 

own, when the storm hit. Information on organization-wide tornado emergency procedures, 

structural damage to the facility, sheltering options, and previous experience with emergencies 

was obtained from these interviews. Attempts were also made to speak with managers and individuals in charge of local businesses, including the hospital, even if they were not involved in the 

tornado in order to understand contingency procedures and the overall response on May 22, in-

 3 The 165 participants include 11 survivors who e-mailed their stories to NIST.
16 NIST Progress Report—Investigation of Joplin Tornado—November 2012

cluding evacuations after the tornado hit. These individuals participated in the NIST interviews 

with their management’s consent.

In addition to survivor interviews, NIST obtained official records from the Missouri Department 

of Health and Senior Services, the Oklahoma State Department of Health, and the Kansas Department of Health and Environment’s Office of Vital Statistics regarding the causes and locations of the 161 fatalities caused by the tornado. NIST also collected a small number of stories 

about the experiences of these deceased victims via interviews with and e-mail from family and 

friends. Additional information on deceased victims was obtained from obituaries, Facebook, 

media accounts, and other websites in which lists of the deceased and information were provided. NIST has received some official records of injuries sustained during the tornado from the 

Missouri Department of Health and Senior Services. A limited amount of information on injuries has been collected through the survivor interviews and media accounts. Transcripts and audio recordings of emergency communications in Joplin on May 22 (911 calls and police and fire 

radio traffic) provided some additional data on fatalities and injuries.

Task 2.2: Collect archival records relating to prior tornado incidents and associated community 

responses, and document codes, standards, and practices for tornado warnings.

NIST collected data from various sources on prior tornado incidents and how communities have 

responded to such incidents. First, all Joplin tornado interviewees were asked about their prior 

experiences in tornadoes, including whether they had experienced a tornado or severe weather 

event, what physical damage occurred, if any, and how they had responded. In addition, NIST

collected reports from previous tornado incidents, including a collection of NWS Service Assessment reports on tornado events and social science research reports on human responses to 

tornadoes. NIST is currently analyzing human responses to past tornadoes, including the Super 

Tuesday event in 2008, the Mother’s Day tornado that hit Oklahoma and Missouri in 2008, and 

the tornado that hit Joplin in 1971, to better explain the social response to the 2011 tornado in 

Joplin. A review of the literature on tornado deaths and injuries is also under way to identify the 

main factors that influence tornado casualties and evaluate whether these played a role in Joplin

in May 2011.

NIST has collected and assessed codes and standards to understand the current state of emergency communications systems for tornadoes. The following is a list of 15 codes and standards relating to emergency communications systems for tornadoes:

1. NFPA 72, National Fire Alarm and Signaling Code (Chapter 24, Emergency Communications Systems) (2013)

2. NFPA 1221, Standard for the Installation, Maintenance, and Use of Emergency Services 

Communication Systems (Chapter 14, Public Alerting Systems) (2010)

3. UL 2017, Standard for General-Purpose Signaling Devices and Systems (2011)

4. UL 1971, Standard for Signaling Devices for the Hearing Impaired (2008)

5. IEC 60849, Standard for Sound Systems for Emergency Purposes (1998)
NIST Progress Report—Investigation of Joplin Tornado—November 2012 17

6. UL 1480, Standard for Speakers for Fire Alarm, Emergency, and Commercial and Professional Use (2010)

7. UL 1989, Standard for Standby Batteries (2010)

8. ANSI S1.13, Measurement of Sound Pressure Levels in Air (2010)

9. ANSI S1.26, Method for the Calculation of Absorption of Sound by the Atmosphere

(2009)

10. ANSI S12.14, Methods for the Field Measurement of the Sound Output for Audible Public Warning Devices Installed at Fixed Locations Outdoors (2007)

11. ANSI S3.2, Method for Measuring the Intelligibility of Speech over Communications 

Systems (2009)

12. ISO 9921, Ergonomic Assessment of Speech Communication (2003)

13. ANSI S3.5, Methods for the Calculation of the Speech Intelligibility Index (SII) (1997)

14. IEC 60268–16, Sound System Equipment—Part 16: Objective Rating of Speech Intelligibility by Speech Transmission Index (2011)

15. 2010 ADA Standards for Accessible Design (Chapter 7, Communication Elements and

Features) (2010)

The first five of these codes and standards focus on the construction, performance, and testing of 

individual physical components of communications systems. Standards 6 and 7 on the list are 

devoted exclusively to specific components of communications systems; these particular standards pertain to speakers and standby batteries. Standards 8 through 15 focus primarily on the 

sound and intelligibility levels of communications, including how to measure each. Although 

FEMA does provide guidance on the use of outdoor warning systems as an alert signal for hazards, no Federal codes or standards exist on the content of emergency messages or the ways in 

which emergency communications systems should disseminate emergency communications before or during tornadoes. Instead, as indicated above, current codes and standards focus on the 

construction, performance, and testing of the physical components of such systems. 

Additionally, there are no Federal laws focused on public broadcasting of tornado warnings. 

While the Federal Communications Commission requires broadcasters to operate in the public’s 

best interest, and most television and radio stations provide severe weather information to varying degrees, there is no Federal law requiring local broadcasters to provide tornado warnings to 

the public before or during an emergency. 

Possibly due to the lack of requirements and standardization, a variety of methods can be used 

and are currently being used to disseminate information during tornadoes. An assessment of 

more than 75 U.S. counties, cities, and towns has shown that emergency information for tornadoes is disseminated using a variety of methods before a tornado hits. Siren systems, for example, may sound differently from one town to the next to alert people of a tornado, or they may 

sound the same across towns for different types of events. In both cases, individuals can become 

confused as to what type of event is actually taking place as they travel from location to location, 
18 NIST Progress Report—Investigation of Joplin Tornado—November 2012

even within the same State. As part of this task, NIST is documenting these differences in emergency communication dissemination techniques.

Task 2.3: Document pre-event archival records for Joplin in relation to tornadoes and the tornado 

warning system.

The purpose of this task is to understand the emergency communications system and procedures 

that were in place in Joplin before the tornado hit on May 22, 2011. According to the data collected, Joplin/Jasper County had emergency plans in place that specified how the siren system 

should operate. The Joplin “zone” consisted of 25 sirens in total that were all tied to the same 

system, that is, if one activated, they all activated. The Joplin sirens sounded if one of the following three conditions was met: (1) the communications operator was notified that a tornado 

had been sighted; (2) a tornado warning was issued by the NWS for Jasper, Newton, or Cherokee 

County; or (3) sustained winds of 75 miles per hour or higher were detected in any part of Joplin. 

The sirens were specified to sound for 3 minutes continuously, one time, and there was no requirement for an all-clear message or siren. Sirens were tested weekly on Monday mornings at 

10 a.m., and sounded for 1 minute during the test. Joplin/Jasper County also had other channels 

for communication of emergency messages, including primary and local Emergency Alert System television and radio stations, Reverse 911 telephone calling, and NOAA Weather Radios 

(purchased on an individual or company-wide basis). 

The “Joplin/Jasper County Local Emergency Operations Plan” (Plan) also presented guidance on 

protective actions in the event of a tornado. The Plan states, “The burden of heeding warnings 

and taking proper action, rests with individual communities and citizens.”4 It also explains that 

while there is no guaranteed safe place during a tornado, some locations are better than others. 

The Plan indicates that the interior part of a basement, preferably under something sturdy like a 

table, is the safest place in the home to take refuge. If a basement is not available, an inside 

room on the lowest floor (for example, a closet or bathroom with no windows) should be sought.

NIST has obtained census information to aid in understanding the demographics of the Joplin 

area, especially the area along the tornado damage path. Demographics for Joplin’s damage 

path, at the census tract level, will be used to provide the foundation for evaluating the generalizability, if any, of the survivor interviewees and to provide the ability to compare the demographics of the deceased victims with the larger Joplin population.

Task 2.4: Collect information from third-party sources including television interviews and newspaper articles.

As mentioned previously, over 100 media accounts of survivor and deceased victim experiences 

were collected. These materials were organized into a database and used to develop the probing 

questions used in the survivor interviews (see Task 2.1). The accounts of survivors will also be 

combined with data from the survivor interviews for analysis in Task 2.5.

 4 Missouri Department of Public Safety State Emergency Management Agency, Joplin/Jasper County Emergency 

Management Agency, Jasper County Officials, and City of Joplin Officials, “Joplin/Jasper County Local Emergency 

Operations Plan,” Joplin, MO, February 2011, page K–8.
NIST Progress Report—Investigation of Joplin Tornado—November 2012 19

Task 2.5: Analyze the data to study the public response to the tornado, including protective actions.

NIST is conducting a qualitative analysis of the interview transcripts, narrative e-mails, and interview notes for the purposes of survivor trend analysis and theory building. Based upon the 

existing probing questions (discussed earlier) and a preliminary analysis of all transcripts, NIST 

developed a list of codes, or categories, used to label sections of the transcript data. For example, one code is “previous experience with tornadoes,” which was used to label all instances 

where interviewees described their previous experiences with storms, tornadoes, or sheltering in 

the event of a storm. During the coding process, analysts labeled sections of the transcripts with 

over 50 different codes. All of the coding was reviewed for consistency by the Task Leader.

Currently, NIST is in the process of identifying properties (components or attributes) and dimensions (modes of variation) of the data within each code/category to create additional categories, 

if necessary. Then, the data will be sorted based upon these categories, including pre-storm individual factors (e.g., prior tornado experience), environmental cues from the storm, individuals’ 

interpretations, and actions taken, to begin to detect data patterns and trends. When trends begin 

to formulate, it is important to test these trends with additional data from this and other studies of 

the human response to tornadoes. Through these methods, a conceptual model of human response to the Joplin tornado will be created.

In parallel with the in-depth trend analysis of survivor stories, NIST is comparing the circumstances and behaviors of survivors with those of persons severely injured or killed by the Joplin 

tornado. Analysis of the fatality and injury data is being conducted to understand the circumstances surrounding each injury or death in as much detail as possible and to help answer questions such as the following: What protective actions (if any) were taken by those injured or 

killed, and how did that compare to actions taken by survivors in the same building, the same 

type of building, or a building nearby? What environmental hazards (e.g., wind speed of the tornado) surrounded the deceased victims versus the survivors or those injured during the storm?

Results of the work being performed for investigation Objective 1 are being used to understand 

the intensity and timing of the tornado hazards in the area of each fatality. Results from Objective 3 are being used to understand the effects of building design and performance for each of the 

fatalities as well as nearby survivors. These results, in addition to the circumstances of and actions taken by those injured and killed, will be compared to attempt to identify the factors that 

influenced whether and how a victim died or was injured on May 22, 2011.

3.5 Response of Buildings, Including Designated Safe Areas

Task 3.1: Collect field data on the performance of buildings, establish environmental conditions 

affecting these buildings, and develop failure hypotheses.

During field deployments, NIST selected approximately 25 commercial and institutional buildings and a number of residential structures, out of the approximately 8000 damaged or destroyed 

buildings, for on-site surveys of their performance during the tornado. The NIST-surveyed 

structures are representative of common construction types and functions in the affected area.
20 NIST Progress Report—Investigation of Joplin Tornado—November 2012

The following construction types are represented among the structures surveyed: steel moment 

frame, concrete moment frame, box-type system with concrete masonry unit (CMU) wall, boxtype system with precast concrete tilt-up wall, light steel frame, unreinforced brick, and wood 

frame. By function, the surveyed structures include critical facilities such as hospital buildings, 

schools, and fire stations; high-occupancy facilities such as large retail stores and churches; 

smaller medical and commercial offices; nursing homes; and single- and multi-family residences. 

Table 3 shows summary information for many of the NIST-surveyed buildings and facilities.

NIST has completed the collection, review, and summarization of field performance data for all 

of the NIST-surveyed buildings. Field performance data collected include photographs taken by 

NIST during the deployments or requested by NIST from others (Structural Engineers Association of Kansas and Missouri, FEMA, St. John’s Regional Medical Center), observation notes, 

measurements, and in the case of Joplin East Middle School, videos from security cameras. 

These data are being used to help understand as-built conditions (e.g., dimensions of building 

components or systems), connection and reinforcement details, damage conditions, and possible 

failure modes and sequences.

Figure 4 shows an example of the field data collected. These photographs, which show a failure 

observed at Joplin East Middle School’s gymnasium, are being used to develop the failure hypothesis for this building. Using the results from work performed pursuant to study Objective 1, 

wind speed and direction time histories can be obtained at specific building locations. These estimated wind velocities are being used in combination with collected field performance data and 

design information to develop and refine failure hypotheses for the surveyed buildings.

Figure 4. Example of photographic field data used in developing a failure hypothesis for the 

gymnasium at Joplin East Middle School. (Photo source: NIST)
NIST Progress Report—Investigation of Joplin Tornado—November 2012 21

Table 3. Damage condition and design information for many of the NIST-surveyed structures

Damage condition information Design information

Collapse of main wind 

force resisting system

Damage or loss of roof 

and/or wall cladding

Loss of functionalityConstruction 

typea Code

Drawings 

obtained 

by NIST

Engineered

Wal-Mart Complete BTS (CMU) BOCA 1990/

IBC 2000 Complete

Joplin East Middle 

School auditorium Complete BTS (CMU) IBC 2000 Complete

St. Mary’s School Complete BTS (CMU) BOCA 1990 Partial

Franklin Technology 

Center Complete BTS (CMU) 1978 Partial

St. John’sb generator 

and chiller buildings Complete BTS (CMU) Not known Partial

Home Depot Complete BTS (Tilt-up) BOCA 1996 Complete

Joplin East Middle 

School gymnasium Complete BTS (Tilt-up) IBC 2000 Complete

St. John’sb main buildings Complete CF, SF Not known Partial

St. Paul’s Church Complete SF BOCA 1996 Partial

Joplin High School 

buildings Complete CF, SF IBC 2000 Partial

Ramesh Shaw Center Complete SF BOCA 1990 Partial

W. Meredith Center Complete SF Not known None

Ozark Center Complete CF Not known Partial

Non-/Marginally Engineered

Single- and multifamily homesSingle- and multifamily homes Complete/

partial/none WF Various years None

Mercy Village Partial WF IBC 2000 Partial

Swanson Office Building Partial WF IBC 2006 Complete

Fire Station #4c Complete CMU Not known None

a BTS = Box-Type System; CF = Concrete Frame; SF = Steel Frame; WF = Wood Frame; CMU = Concrete Masonry Unit. b St. John’s Regional Medical Center.

c

Confirmation of engineered or non-/marginally engineered categorization is pending receipt of design drawings.
22 NIST Progress Report—Investigation of Joplin Tornado—November 2012

Task 3.2: Obtain and review design drawings to refine the failure hypotheses.

NIST has obtained design drawings from the Joplin Building Department for some of the NISTsurveyed buildings. Many of the drawing sets are incomplete and provide only partial design 

information. NIST has obtained structural and architectural drawings for other buildings from 

sources that include St. John’s Regional Medical Center and the architectural and engineering 

design firms of Patterson Latimer Jones Brannon Denham (PLJBD) Inc. and Heery International, 

Inc. The last column of Table 3 shows the status of design drawings obtained to date. As the 

table shows, only partial design information is currently available for buildings at St. John’s Regional Medical Center. Despite significant efforts, NIST has been unable to locate the design 

information for the seven-story reinforced-concrete frame hospital building, including information on the original design and subsequent renovations to exterior windows, as described in 

Sec. 3.2. NIST seeks information from the public identifying potential sources of these documents. 

NIST has reviewed the drawings obtained, and design information from the drawings has been 

compared with field observations to assess consistency between as-designed and as-constructed 

conditions. Design information from the drawings is also being used to support and refine the 

failure hypotheses developed for the different buildings.

Task 3.3: Review performance of designated safe areas, including shelters, safe rooms, and areas of buildings used for refuge.

NIST identified no community storm shelters (defined as meeting the International Code Council’s ICC 500–2008 standard) or community safe rooms (defined as meeting FEMA 361 guidance) in the city of Joplin or the tornado affected areas. Some commercial and institutional 

facilities provided guidance and assistance to move occupants to certain parts of the buildings as 

the tornado approached. Through interviews of survivors, managers, and employees, along with

analysis of design drawings, NIST has identified the areas within some of the commercial buildings that were used as designated safe or refuge areas during the tornado. Several residences 

were identified as having in-residence shelters, including a concrete room in a basement and a 

steel box bolted to a slab on grade. Evaluations of the performance of these designated safe and

refuge areas is beginning, incorporating results from the wind field analysis undertaken for investigation Objective 1 and the fatality and injury data and analysis gathered and performed for

Objective 2.

Task 3.4: Obtain, review, and evaluate appropriate model building code and standards requirements for design of building envelopes and main wind force resisting systems.

Current national codes, standards, and practices do not require conventional buildings, with the 

exceptions of storm shelters and safe rooms, to withstand tornadoes, and do not explicitly consider tornadoes in the design process. However, how buildings that are compliant with current 

building codes perform in tornadoes can indicate how adequate those codes are for designing and 

constructing buildings that are resistant to tornadoes. Table 3 shows that the NIST-surveyed 

buildings were designed to various building codes in effect at the time of their design and construction. NIST also has determined that the City of Joplin has a long history of building and fire 

code adoptions, with records dating back to 1877. NIST has obtained the building codes listed in 
NIST Progress Report—Investigation of Joplin Tornado—November 2012 23

Table 3 and reviewed relevant design requirements pertaining to building envelopes and structural systems as well as requirements for building functionality.

Task 3.5: Assess building performance based on the estimated wind field and on observed damage, relative to model code requirements.

NIST is continuing to assess the performance of selected NIST-surveyed buildings. NIST is using estimated wind speed and wind direction time histories at building locations, which are being 

developed for investigation Objective 1, in conjunction with analyses of ground and aerial photographs to develop hypotheses regarding the damage and collapse sequences. In some instances, where sufficient structural and architectural information is available, NIST estimates of wind 

speeds required to fail different elements of the buildings are being used to validate the failure 

hypotheses, to corroborate wind speed estimates developed for Objective 1, and to compare to 

design wind speeds required by the model building codes. This analysis is considering the performance of both the structural systems and the building envelopes. In some instances, such as 

the main buildings at St. John’s Regional Medical Center, there was almost no damage to the 

structural systems. However, the buildings were rendered completely nonfunctional by extensive nonstructural damage to the building wall and roof systems and subsequent wind and water 

damage to the interior of the buildings.

Due to the large number of residential structures affected by the tornado (approximately 7500 

residential structures), a statistical assessment of the performance of residential structures is a 

more practical approach than would be detailed assessments of individual structures. NIST is 

employing a GIS-based analysis using building characteristics and damage information from the 

Joplin GIS database to correlate the performance of residential construction with estimated wind 

speeds (from Objective 1) and fatalities and injuries (from Objective 2), and to assess the performance of residential structures in comparison with the model code requirements and the estimated tornadic wind speeds. 

3.6 Performance of Lifelines Related to Continuity of Operations of Buildings

NIST has collected field performance data and information on lifeline systems that affect the 

continuity of operations of residential, commercial, and critical buildings in the area impacted by 

the Joplin tornado. Progress on the tasks relating to lifeline performance is described below.

Task 4.1: Gather information on lifeline systems and facilities that support building operations.

NIST has gathered information on the performance of lifeline systems and facilities that support 

the continuity of operations of buildings in Joplin. This includes information on the following:

• Collapse of the open steel frame and transformers of Empire District Electric Company’s 

power substation 59 at 26th Street and Pearl Avenue in Joplin, as well as damage to several transmission lines and approximately 3900 power poles

• Collapses of ancillary buildings that housed the backup generator and chiller equipment 

for St. John’s Regional Medical Center
24 NIST Progress Report—Investigation of Joplin Tornado—November 2012

• High-pressure gas leak at St. John’s Regional Medical Center immediately after the tornado 

• Collapse of an old, unreinforced brick building that was used for storage at the Joplin water treatment facility

• Multiple water leaks resulting in reduced city water pressure

Task 4.2: Evaluate the performance and timelines from disruption to restoration of service (power, water, sewer, and gas systems) and assess the robustness of the systems during the tornado.

Electrical power was lost for an extended period of time throughout much of Joplin due to damaged power substations, transmission lines, and distribution systems. Power substation 59 was 

recently repaired with new transformers installed in June 2012,

5 more than a year after the May 

22, 2011, Joplin tornado. Data collection and performance evaluation are continuing.

Task 4.3: Evaluate the performance of backup power systems with regard to location and protective enclosures.

St. John’s Regional Medical Center’s backup power supply systems were damaged as a result of 

the collapses of the box-type buildings that housed this mechanical equipment. The loss of both 

line power and backup power contributed to the total loss of functionality of this critical facility,

even though the structural systems of the main buildings sustained little damage. NIST is reviewing issues related to the vulnerability of structures that house backup power systems and 

whether changes to standards, codes, and practices could improve the availability of power for 

safe emergency evacuation and ongoing building functionality.

Task 4.4: Collect data on, and assess the causes and extent of, building fires resulting from the 

tornado.

Interviews with Joplin fire officials6 indicated that there were fewer than 10 fires following the 

tornado and that mutual aid departments from around the region handled most of the fires. According to the Joplin fire officials, the fires were caused mainly by residential gas leaks and 

downed power lines, and remained confined to the structures where they originated. The Joplin 

fire officials also indicated that although the fires were limited, the reduction in water pressure 

due to multiple water leaks caused by tornado damage could have contributed to reduced effectiveness in firefighting efforts. Joplin fire officials informed NIST that Joplin had no response 

records for these fires. The Missouri Division of Fire Safety’s Office of the State Fire Marshal 

also had no response records for the fires following the tornado. They indicated that while no 

fire incidents were entered into the National Fire Incident Reporting System (NFIRS) for the 

Joplin area for May 22 or May 23, 2011, NFIRS reporting is not mandatory. NIST recently obtained a list of mutual aid fire departments that responded to the tornado from the Office of the 

 5 R. McKinney, “Empire District Electric Co. replaces transformers damaged during 2011 tornado,” The Joplin 

Globe, June 19, 2012; accessed July 3, 2012, at http://www.joplinglobe.com/topstories/x651523560/EmpireDistrict-Electric-Co-replaces-transformers-damaged-during-2011-tornado. 6 Interviews 1 and 13.
NIST Progress Report—Investigation of Joplin Tornado—November 2012 25

State Fire Marshal and has contacted these departments to request any records they may have

pertaining to fires following the tornado.

3.7 Identification of Codes, Standards, and Practices That Warrant Revision

Task 5.1: Evaluate the results obtained for Objectives 1–4 for potential improvements needed in 

model codes, standards, and practices, and/or for further research needed, and make recommendations for potential changes to increase tornado resilience.

Evaluation of existing standards and guidelines related to the identification of tornado hazards 

has been completed as part of the work performed for investigation Objective 1. Evaluation of 

existing codes, standards, and practices related to emergency communications has been completed as part of the work for Objective 2. Evaluation of model building codes, standards, and practices is nearing completion under Objective 3. As the remaining tasks under Objectives 1–4 are 

completed, those results will feed into the analysis and recommendations for potential revisions 

in order to ultimately improve the tornado resilience of buildings, lifelines, and communities.

3.8 Moving Forward

As described in this report, NIST has made significant progress on the investigation. NIST’s evidence collection is nearly complete. Despite significant efforts, NIST has been unable to locate 

the design information for the seven-story reinforced-concrete frame hospital building at St. 

John’s Regional Medical Center, including information on the original design and subsequent 

renovations to exterior windows, as described in Sec. 3.2. NIST seeks information from the public identifying potential sources of these documents. In addition, NIST is working with the Missouri Department of Health and Senior Services to obtain additional information about those who 

were injured in the tornado and has requested response records for the fires following the tornado 

from mutual aid fire departments that responded to Joplin.

Strong progress has been made on most of the tasks related to the first four objectives of the investigation. NIST is now beginning to tie the results of the work performed under each of these 

objectives together to understand how the tornado hazard, tornado warnings, responses to warnings, protective actions, and building performance all interrelated and led to the outcomes of survival, injury, or death. Work under Objective 5 will proceed as the work under Objectives 1 

through 4 nears completion.