Severe storms in May likely caused billions of dollars in insured losses for the second time, according to a report from Aon.
On May 28, hail and strong winds affected the Austin area, accompanied by heavy rainfall that led to localized flash flooding. Hailstones measuring two inches in diameter were reported in the city. The National Weather Service estimated sustained wind speeds between 65mph and 85mph.
Storms also moved through eastern Texas on May 26 and again on May 28, impacting the Houston region. Local officials reported flash flooding, downed trees and power outages in some neighborhoods.
Aon said the latest storms are part of a broader pattern of severe weather that began on May 22, with repeated convective systems producing hundreds of storm reports, mostly in Oklahoma and Texas. Hailstones larger than four inches were recorded in several rural parts of northern and central Texas, according to the report.
In Oklahoma, storms caused tree damage in the Tulsa area, which in turn affected nearby structures and vehicles.
The late-May activity follows a separate outbreak earlier in the month, which brought tornadoes and large hail across several central states. That event is estimated to have resulted in $4 billion to $7 billion in insured losses, according to Steve Bowen, chief science officer at Gallagher Re.
“Calling severe convective storms a secondary peril is doing a disservice to how impactful this continues to be,” Bowen said, as reported by Best Wire. “This is a primary peril.”
Meanwhile, Aon noted that severe convective storms have produced more than $20 billion in annual insured losses in eight of the past nine years. Losses have been driven by hail, tornadoes, straight-line winds and flooding, especially in high-population and high-exposure areas.
Storm activity continued through the end of the month. On May 30, the National Weather Service reported that damage observed in one Kentucky community was consistent with an EF-1 tornado, with wind speeds of at least 86mph. Additional damage assessments were underway in other parts of the state.
In Canada, wildfire conditions remain elevated due to prolonged dry and warm weather. Fires have burned more than 300,000 acres in Manitoba, prompting evacuation orders for roughly 17,000 people. Several provinces have issued burn restrictions and air quality alerts as fire conditions persist.
Storm systems also caused damage in other parts of the world as May came to a close. Tornadoes, hail, and flooding were reported in Australia, Romania, and Chile. In the Eastern Pacific, Tropical Storm Alvin, the first named storm of the 2025 season, brought heavy rain and wind to coastal areas of Mexico.
As hurricane season begins in the Atlantic and Pacific basins, insurers and reinsurers are monitoring weather developments and ongoing loss trends. Rising losses linked to convective storms and wildfires remain a factor in property catastrophe markets.
