Insured natural catastrophe losses continue to be driven by hail damage during severe convective storm outbreaks, highlighting the need to mitigate and prevent such damage.

In addition to more frequent storms, larger hail stones are becoming more frequent, prompting some policyholders to consider installing more robust roofing materials.

A recent report from Gallagher Re, the reinsurance business of brokerage Arthur J. Gallagher & Co., shows that severe convective storms caused $11 billion of the estimated $20 billion in first-quarter insured natural catastrophe losses.

The report said this was the second-largest first-quarter loss total attributed to severe convective storms, trailing only 2023’s record $15 billion.

“Once again, SCS has driven most of the narrative for the industry. It’s been a continuation of the last year,” said Steve Bowen, Chicago-based chief science officer with Gallagher Re.  “The reality is that we’re seeing more and more of these smaller-scale events, notably severe convective storms, which are really aggregating to much, much higher losses,” he said.

Larger hailstones, being observed more often, might lead to more significant problems for insurers. “It definitely warrants additional discussion around the fact that we did have a record number of large hail reports in the U.S. of hailstones larger than two inches or greater,” Mr. Bowen said.

Hail “has been the culprit for loss for so long that it’s something that needs to be looked at much more seriously,” said Marty Smuin, Salt Lake City-based CEO of Arturo Intelligence Inc., an insurtech focused on property data and imagery.

“When you look at convection storms in general, they’re much more frequent, and they’re much more powerful,” he said.

A first step in developing a mitigation strategy is to assess what types of weather events might hit a geographic area and ensure that buildings are designed to withstand the exposures, Mr. Smuin said.

He added that a structure’s roof is the obvious first line of defense. “The roof is where you’ve got to apply the technology to defend against the storms that are most prevalent to any area,” he said.

Ian Giammanco, managing director of standards and data analytics and lead research meteorologist for the  Insurance Institute for Business & Home Safety Research Center in Richburg, South Carolina, said building materials manufacturers are beginning to address the hail issue.

“Most building materials cannot withstand hail. They’re not designed to,” Mr. Giammanco said. He added, however, that  “there are a growing number of roofing products that are starting to offer mitigation potential. We’ve seen the manufacturers make their products better.”

Materials such as composites and metal offer better hail protection than traditional asphalt shingles. Still, the composites can cost more, and metal may present a “cosmetic” problem to a builder or owner.

“We’re seeing emerging composite shingles that do offer good performance. Those materials truly offer long-term performance. The next step is, can some of the good-performing new materials come down in cost enough to compete with asphalt shingles?” Mr. Giammanco said.

Metal roofing, he said, performs well. “The metal roofing typically does not crack under hail impact,” but “there's the cosmetic issue,” he said.

Roofing material choice can influence an insurer’s view of property risk, said Stephen Penwright, property technical director for U.S. national accounts at Zurich North America.

“If a customer has numerous locations in a high-hazard hail zone and chooses to install more hail-resistant roofs on all of them, that could make the risk more attractive to a property insurance underwriter,” he said.

Mr. Penwright added, however, that “installing hail-resistant roofs on many properties would likely represent a cost that the company would have to weigh with their insurance partner.”