NIST: Joplin tornado highlights need for building design, construction standards

The massive tornado in Joplin was rated by the National Oceanic and Atmospheric Administration (NOAA)’s National Weather Service (NWS) as category EF 5, the most powerful on the Enhanced Fujita scale. The multiple-vortex storm impacted an area 35 kilometers (22 miles) long, destroyed some 8,000 structures in its path and killed 161 people. This makes it the single deadliest tornado in the United States in the sixty-three years that official records have been kept.

In the majority of cases, the study found that regardless of construction type, buildings did not adequately protect occupants and that Joplin residents had limited access to underground or tornado-resistant shelters. The majority of deaths (135 or 83.8 percent) were caused by impacts associated with building failure. Virtually all of the buildings in which people died were affected by wind speeds equivalent to an EF-3 tornado or higher on the Enhanced Fujita scale.

Multiple factors contributed to a delayed or incomplete response by people in the tornado’s path, including lack of awareness of the tornado’s approach, confusion about or distrust of the emergency messages prior to the tornado’s arrival, and an inability to perceive risk due to the conflicting information. While outdoor siren systems prompted many residents to seek further information about whether or not there was a true hazard, people were often confused by multiple information sources.

Disasters such as the Joplin tornado are devastating, but out of tragedy can come important opportunities to understand, evaluate and learn from the performance of structures, emergency communications and human behavior during catastrophic events,” said Letvin.

Based on findings from the investigation, NIST developed 16 recommendations for improving how buildings and shelters are designed, constructed and maintained in tornado-prone regions; and for improving the emergency communications that warn of imminent threat from tornadoes.

The key recommendation proposed in the report is “the development and adoption of nationally accepted performance-based standards for the tornado-resistant design of buildings and infrastructure to ensure the resiliency of communities to tornado hazards.” This includes a call for designing and constructing essential buildings — such as hospitals and emergency operations centers — and infrastructure to remain operational in the event of a tornado.

Additionally, the report’s authors recommend the development of methods that will ensure all building components and systems meet the proposed performance objectives.

The report also recommends uniform national guidelines be developed that enable communities to create the safest and most effective public sheltering strategies. Shelters, the report states, should be installed in new and existing multi-family residential and commercial buildings, schools and in buildings with assembly occupancies (such as theaters and places of worship) located in tornado hazard areas.

Also needed are nationally accepted codes and standards, as well as uniform guidance for clear, consistent and accurate emergency communications, according to the report. This will require the collaboration of emergency managers, the NWS and the media to develop and execute a plan to ensure that appropriate and timely warning information improves the situational awareness of the people who would be affected by an event, including emergency responders.

The release notes that the NIST report includes a number of recommendations for future research and development of technologies and strategies to advance tornado wind measurements, strengthen emergency communications, increase warning time, derive more accurate tornado hazard maps and significantly improve public response during tornado events.

NIST invites comments on the draft report and recommendations, which must be received by 5 p.m. Eastern Time on Monday, 6 January 2014. Comments may be submitted via e-mail to or mailed to NIST Technical Investigation Joplin, 100 Bureau Dr., Stop 8611, Gaithersburg, Md. 20899-8611.

The NIST investigation of the Joplin tornado was conducted under the provisions of the National Construction Safety Team (NCST) Act. The act gives NIST the responsibility for conducting fact-finding investigations of building failures that resulted in substantial loss of life or that posed significant potential for substantial loss of life.

The Joplin tornado investigation builds on a partnership between the agency’s Disaster and Failure Studies Program and the interagency National Windstorm Impact Reduction Program.

— Read more in News Briefing Introductory Remarks, Howard Harary, Acting Director, Engineering Laboratory; News Briefing Opening Statement, Eric Letvin, Director of Disaster and Failure Studies; Draft Report and Recommendations