Tornado Alley Eastward Shift Adding Risk Concerns, Modeler Says

The peak of tornado season may be behind us, but the eastward expansion of what has been traditionally known as tornado alley into more populated areas may continue raising awareness of the growing insurance risk long for some time.

Record tornado activity in Illinois, Indiana, and Wisconsin this year drove elevated claims and increasing risk because of population exposure. Increased losses in new areas weren’t from raw tornado counts across the U.S., but from increased risk exposure, according to one industry catastrophe modeler.

Illinois led all states in tornado activity in this year, with 220 confirmed tornadoes through the end of July. Indiana and Wisconsin also set record‑high numbers.

Related: Tornadoes in Illinois and Indiana Leave Residents Grappling With Damage

Weather experts say the tornado alley shift — beyond areas like Texas, Oklahoma, Kansas — is due to a warming climate that helps transport warmer and more-humid air farther north and east than in the past.

Illinois saw its third distinct spike in five years, and the year’s volume already exceeds 2024 and 2025 combined, with average severity up by a factor of four since 2022, according to Verisk.

The 2026 Illinois surge has been concentrated, driven mainly by occurrences in June and July, and by strikes in Cook, Kankakee and Coles counties. Kankakee saw unusually high severity with a $104,000 average estimate, according to Verisk data.

Wisconsin experienced an even sharper spike, up 672% year-over-year, but that spike is due largely to a single concentrated event in Winnebago County in July the data show.

“The tornado alley’s kind of expanding or shifting a bit eastward, and so I think as we think about that from an insurance perspective and think about ‘What does that mean for insurers,’ I think one of the largest concerns is there’s a lot more population as you move eastward,” said Tory Farney, vice president of Verisk Weather Solutions.

Their data show the numbers of tornadoes aren’t going up, but the losses have tended to be worse when they strike.

Related: Report: Claims Severity Reaches All-Time High, Frequency Declines

Overall, national tornado claim volume is down, but severity is up. Tornado volume peaked in 2023 and has declined every year since. However, the average estimated reconstruction value has risen every year, and is now 72% above 2022, the modeler’s figures show.

There’s still some debate as to why is the shift occurring, and if it will last.

“It’s definitely measurable and we have strong evidence that it is occurring. But will it continue to occur, will it revert back at some point? I think it’s still a point of uncertainty,” Farney said. “There’s certainly the climate change aspect of that as a potential driver but there’s also some other things with more recent research that people are looking into around how these large-scale oscillations like the Pacific decadal oscillation or the Atlantic multi-decadal oscillation could play roles in the shifting of these large-scale patterns of where these weather systems are tending to set up across the country.”

He added, “and so, there’s a little bit of question there.”

The shift isn’t just tornadoes, other perils like severe thunderstorms and hail seem to have been moving to where they are more frequent in the east in recent years, as part of a broader trend. Hailstorms drove record insured damages as severe convective storms become more common and damaging, popping up in new places, according to a report from Allianz.

“Now we see very similar trends in hail as we do tornadoes with the eastward shift, and so it’s not just a single peril, tornado, that’s shifting,” Farney said. “It’s everything that kind of comes with severe thunderstorms. So, it’s hail, it’s wind, it’s instances of flash flooding that are sometimes associated with that — it’s kind of all of those threats, all kind of moving in the same way with that increased frequency more eastward.”

According to Verisk, severe thunderstorms now rank among the industry’s most significant catastrophe loss drivers. A report out last year from the firm showed a 59% increase in severe thunderstorm events generating more than $1 billion in insured losses during the period from 2020 to 2024 compared with 2015 to 2019. Frequency perils such as severe thunderstorms, wildfires, winter storms and inland flooding now account for $98 billion of the industry’s modeled $152 billion average annual catastrophe losses.

Verisk found that property exposure in its modeled countries grew an average of 7.3% per year between 2020 and 2024, which the firm says is due to a combination of new construction and higher replacement costs.