The Worst Tornado Outbreaks in U.S. History The eight worst tornado outbreaks in the United States have accounted for nearly $40 billion dollars in damage, are responsible for 17,525 injuries, and tragically over 1,500 fatalities. I wanted to share today a project I have been working on that tells the story of these incredible severe weather outbreaks. Tornado Days , built with the D3.js Javascript library, is an experimental way of expl