The Joplin Tornado: Lessons Learned from the NIST Investigation

The EF-5 tornado that devastated Joplin, MO the afternoon of Sunday May 22, 2011 damaged or destroyed over 8,000 structures (~30% of Joplin) and caused 161 fatalities and over 1000 injuries, and approximately $1.8 billion insured property losses. The large number of fatalities and high economic loss make the Joplin tornado both the deadliest and the costliest single tornado since official records began in 1950. The high death toll occurred despite an effective tornado warning time of about 25 minutes, which is nearly double the national average warning time. The National Institute of Standards and Technology (NIST), under the authority of the National Construction Safety Team Act, conducted an investigation to assess the conditions that led to the large number of fatalities and injuries. The NIST investigation focused on the following technical areas: (1) the tornado hazard characteristics and associated wind field, (2) the pattern, location, and cause of fatalities and injuries, and associated performance of emergency communications systems and public response to warnings and (3) the response of residential, commercial, and critical buildings, including the performance of designated safe areas and of life-lines that pertain to the continuity of building operations.

NIST has developed a set of findings and recommendations pertaining to the above-mentioned technical areas, summarized in this paper, with the goal of improving public safety in tornadoes. These findings and recommendations are intended to provide the basis for: (1) Potential improvements to building code requirements for design and construction of buildings, designated safe areas, and lifeline facilities in tornado-prone regions; (2) Potential improvements to guidance for tornado warning systems and emergency response procedures; and (3) Potential improvements to emergency communications codes, standards, and practices.