Lessons Learned and the Path Forward

Abstract

We began this book with the goal of determining the extent to which extreme weather and extreme vulnerability were responsible for the historic 2011 tornado death toll. Our analysis finds that extreme weather—meaning the number, strength, and location of the year’s tornadoes—can explain much of the deadly season. We have employed a variety of approaches to reach this assessment, including out-ofsample projections based on regression analysis of tornado fatalities and applying recent ratios of fatalities to damage, buildings damaged, and injuries to the impacts of this year’s tornadoes. While the different methods lead to slightly different projections, each approach implies that based on the impacts observed, we would have expected a death toll not seen in decades in the United States. Admittedly, each of the approaches we have used has its limitations, and this is why we have employed a variety of approaches.