Fewer than 450 tornadoes were reported in the U.S. this year as of June 1 — an historic low going back to 1950 — but a handful of severe weather outbreaks still caused problems in May, according to Aon’s Impact Forecasting.

Four separate severe weather outbreaks hit the United States in May, causing significant hail and wind damage, according to Impact Forecasting’s May Global Catastrophe Recap report.

The hardest-hit areas: From the Rockies to the Mid-Atlantic. Among the worst weather events to hit in the month was catastrophic flooding in Ellicott City, Md., which Impact Forecasting noted was the second time this has happened since 2016.

Impact Forecasting calculated that just two of the four weather events caused at least $2.3 billion in estimated economic losses and that public/private insurers would cover more than 75 percent of the total.

There’s no final tally yet, but Impact Forecasting said it will be “even higher.”

Additional North American thunderstorm damage occurred in areas of Canada’s Ontario and Quebec, with one event costing insurers nearly $325 million, according to catastrophe analyst CatIQ. Most of the hail and wind damage occurred in Ontario, making it the costliest thunderstorm in the province since 2013.

There was a busy storm season both for the U.S. and globally in May. Some highlights:

• Flooding along the Yangtze River Basin and elsewhere in China damaged more than 75,000 homes, leading to total combined economic losses above $400 million.
• Convective storm damage struck in Asia and Europe. In India alone, nearly 300 people died in thunderstorm-related incidents. An active storm pattern in Central and Western Europe at the end of May will likely lead to hundreds of millions of dollars in insurance payments.
• In Australia, the Insurance Council of Australia declared an insurance catastrophe after floods in New South Wales. Preliminary insurance payouts came close to $21 million.
• Two rare tropical cyclones made landfall in Somalia and Oman in a matter of days of each other. Tropical Cyclone Sagar became the strongest storm to strike Somalia on record, reaching speeds of 60 mph, and also left heavy damage during its path through the Gulf of Aden. Tropical Cyclone Mekunu made landfall in Oman as a 115 mph Category 3 storm. Widespread wind and flood damage was reported.
• Subtropical Storm Alberto developed in the Gulf of Mexico and made landfall as a 45 mph system near Panama City, Fla. Heavy rains and isolated tornadoes impacted an area from Florida to Michigan. At least seven people died in Cuba due to extensive flooding.
• Hawaii’s Kilauea volcano erupted beginning May 3 and continued to spewing ash into the atmosphere and sending lava flows into residential areas. Hundreds of homes and other structures were destroyed.

Source: Aon/Impact Forecasting