Dewey Kahawai was sleeping when he heard a knock on his bedroom window. 

“I sprang out of bed and thought, ‘Oh my gosh, someone’s trying to get into my house,’” he said.

Then, he heard thumps on the roof, and he knew: A hailstorm was sweeping through Colorado’s eastern plains, 50 miles north of Denver. Other residents reported seeing ice balls almost the size of baseballs.

Kahawai’s house was fine. But by morning his phone was blowing up with calls and texts. Kahawai runs his own company, American Pride Autoglass. For two weeks, he worked 14-plus-hour days, crisscrossing town.

“There were people's cars that were literally destroyed,” he said. “Three- or four-inch diameter holes through the glass on their vehicles; front windshields with six, eight hits.”

He estimated he alone attended to hundreds of thousands of dollars’ worth of damage.

Ian Giammanco, a lead research meteorologist at the Insurance Institute for Business and Home Safety, said hail impacts to cars, crops and roofs add up.

“It's not as big a life safety threat as say a storm surge or flash flooding,” Giammanco said, “but it happens every single year and it’s costing us just tens of billions of dollars.”

The costs are increasing, pushing up insurance premiums in several states. The trend is partly explained by more people moving to places with hailstorms. Additionally, some researchers think climate change could mean fewer storms, but more destructive hail. 

But there’s still a lot we don’t know about hail, Giammanco said. To find answers, he is part of a huge team of researchers working on the largest study of hail in 40 years. The project, called ICECHIP, is supported by $11 million from the National Science Foundation. For six weeks this summer, scientists chased hailstorms around the Great Plains and Mountain West.

“There were some fantastic storms,” said Becky Adams-Selin, a scientist at Atmospheric and Environmental Research and the principal investigator on ICECHIP.

The research teams flew drones into clouds and measured the hail that fell on the ground.

“How fast does a hailstone fall? How does it melt? Like again, all things that seem pretty basic, but are surprisingly difficult to try to unpack,” Adams-Selin said.

Piecing together all this data, she said, could tell us why certain conditions in the sky — like temperature, humidity, wind speed — produce a different amount of hail that falls to the ground.

This data could be used to give more detailed warnings and share information.

“The hail swath is going to be about five miles wide, and it'll probably produce hail for an hour, and it's going to be blown by winds at 20 miles an hour,” Adams-Selin said, as an example of what an improved alert could sound like. “That would be awesome.”

It could give people time to drape netting over crops and pull cars into the garage.