The U.S. Is Getting More Heavy Tornado Days. Scientists Are Trying to Figure Out Why.

Key Facts

The number of tornadoes so far in the United States this year is just above average.
Tornadoes tend to travel in packs these days, often with a dozen or more forming in the same region on the same day.
The total number of tornadoes in the United States each year has stayed relatively consistent over the last several decades, but they now happen in more concentrated bursts over fewer days during the year.
In the 1950s through the 1970s, on average about 69 percent of tornadoes in the United States happened on days with less than 10 tornadoes, and about 11 percent happened on days with 20 or more tornadoes.