November 29, 2007
+ High Resolution (Credit: NOAA)
Enterprise (Ala.) High School officials and students followed appropriate safety measures prior to and during the March 1 tornado outbreak which killed eight students, but the event further demonstrated the need for such facilities to have hardened safe rooms, according to a NOAA National Weather Service assessment released today. The eight students were killed as a concrete wall collapsed onto them while seeking shelter from the EF4 tornado.
“The tragic events of March 1 show that even when people have ample time and opportunity to take cover from a devastating tornado, the need for proper shelter is imperative,” said retired Navy Vice Adm. Conrad C. Lautenbacher, Ph.D., under secretary of commerce for oceans and atmosphere, and NOAA administrator. “Despite warning lead times that exceeded national standards, 19 lives were lost. Our team concluded that survival in violent tornadoes often depends on reaching an adequate hardened safe room.”
In addition to the eight student fatalities in Enterprise, an additional six people died in a mobile home park near Newton, Ga., and five others in Alabama and Georgia.
A total of 31 verified tornadoes struck 45 counties in Georgia and southern Alabama, including 13 strong or violent tornadoes (EF2 or greater on the Enhanced Fujita Scale). The deadliest was the EF4 in Enterprise.
Hardened safe rooms, lined and topped with concrete and without windows, are designed to withstand severe sustained winds and wind gusts. However, these interior safe rooms are not practical for mobile homes, which often move off their foundation during extreme winds. The team concluded that a necessary component for tornado safety in a trailer park is a hardened safe room easily accessed and shared by the community.
Risk of fatality in a mobile home is 15 to 20 times greater than for those in permanent structures. Only seven percent of U.S. residents live in mobile homes, yet this is where around 50 percent of tornado fatalities occur. However, even permanent structures are at risk in tornadoes rated EF3 or higher.
“We saw permanent structures completely removed from their foundations during the March 1 outbreak,” said Glenn Lussky, meteorologist-in-charge of the National Weather Service office in La Crosse, Wis., and team lead for the service assessment. “Hardened safe rooms are essential for tornado safety. This is perhaps the only thing that could have made a difference for the students in Enterprise.”
At the time of the deadly outbreak, school officials were criticized for not releasing the students prior to or during the outbreak. Students and staff at Enterprise High School sheltered in place for two and half hours.
“Dismissing the students could have been just as dangerous,” said Lussky. “Tornado warnings were in place the entire time, and the team agreed that shelter in place was the best response.”
Since the Enterprise tornado outbreak, the National Weather Service has moved from a county-based system of warnings to a more geographically specific storm-based warning system. The new storm-based warnings provide more precise information about the location of severe weather and the direction it is expected to move.
Testing revealed that storm-based warnings would have reduced the warning coverage area by 58.4 percent. Nevertheless, the high school and the town of Enterprise would have been under a warning for the same amount of time.
“Three successive supercell thunderstorms moved over or near Enterprise during that time,” said Lussky. “We believe the warnings and response would have been the same under storm-based warnings. This is just one of those cases where everyone did everything they could. The only thing left is the hardened safe room.”
The National Oceanic and Atmospheric Administration, an agency of the U.S. Commerce Department, is celebrating 200 years of science and service to the nation. From the establishment of the Survey of the Coast in 1807 by Thomas Jefferson to the formation of the Weather Bureau and the Commission of Fish and Fisheries in the 1870s, much of America's scientific heritage is rooted in NOAA.
NOAA is dedicated to enhancing economic security and national safety through the prediction and research of weather and climate-related events and information service delivery for transportation, and by providing environmental stewardship of our nation's coastal and marine resources. Through the emerging Global Earth Observation System of Systems (GEOSS), NOAA is working with its federal partners, more than 70 countries and the European Commission to develop a global monitoring network that is as integrated as the planet it observes, predicts and protects.The service assessment “Tornadoes in Southern Alabama and Georgia on March 1, 2007” is available online.