Wednesday, 25 January 2012: 11:45 AM
Extreme Weather, Extreme Vulnerability and the 2011 Tornado Season
Room 252/253 (New Orleans Convention Center )
The death toll from the 2011 tornado season currently stands at 546, the deadliest year for tornadoes in the U. S. since 1936. The season also stands as the greatest outlier in U. S. history, as the death toll is about 10 times greater than the recent average for annual tornado deaths. Natural disasters are a product of the underlying natural events and human vulnerability. The question naturally arises then whether this extremely deadly season was the result of extreme weather - the number and strength of tornadoes - or extreme societal vulnerability. The answer to this question then could have implications for the warning process, building practices and housing choices, and public policy. We address the question of whether the 2011 tornado death toll was a function of weather or societal vulnerability by applying a regression model developed by the authors to analyze determinants of tornado casualties for out-of-sample predictions of 2011's deadliest tornadoes. In general the model predicts the fatality totals observed reasonably well, with the actual total often within the 95% confidence interval for the point estimate. Generally 2011 fatalities are what would have been expected given the pattern of fatalities for tornadoes in the US over the past twenty five years. Particularly the model under-predicts fatalities for the Tuscaloosa EF-4 and Joplin EF-5 tornadoes, predicts fatalities rather well for the long track northern Alabama EF-5 tornado, and predicted a much higher death toll than observed in the El Reno, Oklahoma EF-5 tornado.