Dan Chavas in The Conversation:
Violent tornado outbreaks, like the storms that tore through parts of St. Louis and London, Kentucky, on May 16, have made 2025 seem like an especially active, deadly and destructive year for tornadoes.
The U.S. has had more reported tornadoes than normal – over 960 as of May 22, according to the National Weather Service’s preliminary count.
That’s well above the national average of around 660 tornadoes reported by that point over the past 15 years, and it’s similar to 2024 – the second-most active yearover that same period.
I’m an atmospheric scientist who studies natural hazards. What stands out about 2025 so far isn’t just the number of tornadoes, but how Tornado Alley has encompassed just about everything east of the Rockies, and how tornado season is becoming all year.
Why has 2025 been so active?
The high tornado count in 2025 has a lot to do with the weather in March, which broke records with 299 reported tornadoes – far exceeding the average of 80 for that month over the past three decades.
March’s numbers were driven by two large tornado outbreaks: about 115 tornadoes swept across more than a dozen states March 14-16, stretching from Arkansas to Pennsylvania; and 145 tornadoes hit March 31 to April 1, primarily in a swath from Arkansas to Iowa and eastward. The 2025 numbers are preliminary pending final analyses.
While meteorologists don’t know for sure why March was so active, there were a couple of ingredients that favor tornadoes:
- First, in March the climate was in a weak La Niña pattern, which is associated with a wavier and stormier jet stream and, often, with more U.S. tornadoes.
- Second, the waters of the Gulf were much warmer than normal, which feeds moister air inland to fuel severe thunderstorms.
By April and May, however, those ingredients had faded. The weak La Niña ended and the Gulf waters were closer to normal.
April and May also produced tornado outbreaks, but the preliminary count over most of this period, since the March 31-April 1 outbreak, has actually been close to the average, though things could still change.
What has stood out in April and May is persistence: The jet stream has remained wavy, bringing with it the normal ebb and flow of stormy low-pressure weather systems mixed with sunny high-pressure systems. In May alone, tornadoes were reported in Colorado, Minnesota, Delaware, Florida and just about every state in between.
Years with fewer tornadoes often have calm periods of a couple of weeks or longer when a sunny high-pressure system is parked over the central U.S. However, the U.S. didn’t really get one of those calm periods in spring 2025.
Tornado Alley shifts eastward
The locations of these storms have also been notable: The 2025 tornadoes through May have been widespread but clustered near the lower and central Mississippi Valley, stretching from Illinois to Mississippi.
That’s well to the east of traditional Tornado Alley, typically seen as stretching from Texas through Nebraska, and farther east than normal. April through May is still peak season for the Mississippi Valley, though it is usually on the eastern edge of activity rather than at the epicenter. The normal seasonal cycle of tornadoesmoves inland from near the Gulf Coast in winter to the upper Midwest and Great Plains by summer.
Rat Bastard Senator Hawley doesn’t want his face to be eaten by leopards.