For 40 days this summer, Illinois atmospheric scientist Victor Gensini and roughly 100 other specialists and students traveled the Great Plains chasing storms. More specifically, they investigated severe convective storms, the weather events that cause tornadoes and thunderheads. But their true quarry was something more elusive: hail.
“It’s just an underappreciated peril that causes billions of dollars in loss every year,” said Gensini, based at Northern Illinois University in DeKalb.
Ice falling from the sky is notoriously difficult to study, in part because it melts as it falls or soon after. The project, called the In-situ Collaborative Experiment for the Collection of Hail In the Plains for the pitch-perfect acronym ICECHIP, was the first of its kind in more than four decades and took eight years to organize. As scientists seek to fill gaps in our knowledge of how and where hail falls, climate change seems to be altering the hailstones themselves. A warmer atmosphere, research from Gensini and others published last year in Nature suggests, can make hail bigger, heavier and more damaging to homeowners than more dramatic weather events, including some hurricanes and wildfires.
“Nobody’s evacuating because there’s a hailstorm,” said Trent Ford, the Illinois state climatologist. “Hailstorms are sort of unremarkable at first take. But then collectively, we see these kinds of financial problems that come from them.”
Severe convective storms resulted in $60 billion in losses in 2024, according to the Insurance Information Institute, and insurers blamed hail as one reason for recent hikes to homeowners’ insurance rates in Illinois.
State Farm announced last month that the company would increase rates for more than 1.5 million homeowners in the state by an average of more than 27 percent beginning Aug. 15. The company said it paid out $1.26 for every dollar it collected from Illinois policyholders in 2024, what insurance companies refer to as a loss ratio.
The rate hike followed another made by Allstate, which increased Illinois home insurance rates about 14 percent beginning in February.
State Farm’s move prompted pushback from state officials. They say they suspect that weather events in the state don’t justify such an increase and that the Bloomington-based company might be trying to offset losses in other places as climate disasters mount. One in 3 Illinois homeowners has an insurance policy with State Farm, and the increase will cost the average customer $750 more a year.
“When insurance companies suddenly want to increase customer premiums $750 and blame it on their loss ratio, we simply ask them: Prove it,” wrote Illinois Gov. JB Pritzker, State Senate President Don Harmon and State House Speaker Chris Welch in an op-ed published in the Chicago Tribune.
State Farm disputes that costs from other states are seeping into Illinois bills.
“Our recent rate filing in Illinois reflects the risk we see in this state,” said Gina Morss-Fischer, a spokesperson for the company. “Trends in recent years also indicate damaging storms are more frequent here.”
The company paid more in hail damage claims in Illinois than any other state except Texas in 2024, Morss-Fischer said.
The big rate increase continues a statewide trend. Illinois homeowners’ rates have gone up 50 percent over the last three years, more on average than in any other state but Utah, from roughly $2,000 to roughly $3,000, said Abe Scarr, state director for Illinois PIRG, a public-interest advocacy group.
At the end of last month, state Sen. Laura Fine introduced a bill to make insurers explain in detail the reasons for any rate increase above 10 percent and to ban the companies from using homeowner insurance premiums to pay for CEO compensation or political contributions. The legislation would also launch a grant program to help struggling renters and homeowners keep up with increases.
Illinois legislators are now also considering whether they should require a review of insurance rate hikes, as most other states do. “When it comes down to insurance practices that are impacting consumers, I think we need greater regulatory tools, greater regulatory insight and greater accountability as we navigate the challenging waters ahead,” Scarr said.
The effects of climate change on extreme weather is part of that challenge. Meanwhile, damage to pricey items like computers, tablets and phones is driving up claim amounts, while ongoing development puts more homeowners in storms’ paths, said Ashish Sharma, the head of climate and urban sustainability at the University of Illinois System’s Discovery Partners Institute.
Homes can also sustain damage from straight-line winds, derechos and downbursts, he said. Climate change does seem to be exacerbating those extreme events.
“When you ask people, ‘How does climate change affect you?’ Everyone’s like, ‘Well, it doesn’t affect me,’” Gensini said. “Yeah, it does. Are you paying insurance? Every year, every month, you’re paying for this change, whether or not you realize it.”
There may be ways to address the additional cost of claims other than raising rates, researchers say. Updated building codes, for example, could help reduce the risk of damage by requiring developers to use more resilient building materials. Materials scientists who studied the severe convective storms this summer also tested a new composite roofing material, finding that it held up better to hail than typical asphalt shingles.
While legislators debate whether to require an insurance rate increase review, Northern Illinois University and University of Wisconsin-Madison scientists plan to open a center in the fall with the help of National Science Foundation funding that will bring researchers together with businesses to share knowledge about the economic perils of convective storms. The idea is to help answer questions and offer potential solutions for insurers and other businesses, said Gensini, who will be the Center for Interdisciplinary Research on Convective Storms’ director.
“I’m hopeful that this center can become a third-party neutral arbitrator,” Gensini said. “We don’t think that a lot of the models that insurance companies are using right now are properly calibrating and understanding the true risk associated with convective storms.”
The partnership could be particularly valuable as staffing cuts and proposals for sharply reduced funding by the Trump administration have upended the National Oceanic and Atmospheric Administration, which develops and distributes the most recent science and warnings about extreme events.
“Some of the best modeling approaches, the best analysis, the best science, has been over the last 50 years or so, federally funded in the United States,” said Ford, based at the Prairie Research Institute at the University of Illinois. “At the same time that we’re seeing more of these issues come up in the insurance industry, we are undercutting the quality and the availability of the information.”
Susan Cosier reports for Inside Climate News.