Are tornadoes getting worse, or does it just seem that way? NPR's Ari Shapiro discusses the recent series of devastating tornadoes across the plains states.

Tornadoes and sever storms hit several parts of the US on Friday, leaving at least 23 dead and thousands of buildings damaged.

It's getting more common for a lot of tornadoes to form over a big area in a short period of time. But the total number of tornadoes each year in the U.S. is stable.