Fatality Prediction for the 2011 Tornado Season Based on Historical Extreme Weather Data

Abstract

The 2011 tornado season resulted in 553 deaths, the most in a year in the United States since 1925. Natural events and human vulnerability combine to produce natural disasters, and so this work explores whether extreme weather—the number and strength of tornadoes—or extreme societal vulnerability drove the 2011 tornado death toll. The main analysis uses out-of-sample predictions for 2011 from a regression model of tornado fatalities. Generally, 2011 fatalities were in line with expectations based on the pattern of fatalities in the United States over the period 1990–2010, although the deadliest tornado over this period resulted in 36 deaths. The best regression models predict a season death toll of around 500 and a single tornado with 150 deaths. Recent ratios of injuries and property damage to fatalities also support the conclusion that extreme weather drove the 2011 tornado death toll.