The outbreak marked the first time in more than 20 years that two tornadoes with the highest ranking on the Enhanced Fujita scaled (EF5) occurred on the same day. An EF5 twister touched down in Smithfield, Miss., and Hackleburg, Ala., on April 27. A dozen EF4 tornadoes have been confirmed during the span of severe weather, AIR says in a statement.

More than 350 people are said to have died from the severe weather across seven states.

The National Oceanic and Atmospheric Administration says at least 305 tornadoes hit the U.S. April 25-28, making it the largest outbreak in history.

A tornado on April 27 that struck Tuscaloosa and Birmingham, Ala., was an EF4. It remained on the ground for 90 minutes and traveled 80 miles, reports AIR, which called Alabama the worst-affected state. Thirty-eight of 67 counties have been declared disaster areas, as many as 5,000 properties were destroyed, and Insurance Commissioner Jim Ridling estimates insured losses in the state could reach the $2 billion mark experienced after 2004’s Hurricane Ivan.

AIR says it sent in post-disaster teams in Alabama to assess building performance. Large commercial structures in Tuscaloosa were “reduced to rubble,” reports Tim Doggett, principal scientist at AIR. In two suburbs of Birmingham, “the damage in these mostly residential areas was near total along the direct path, leaving only slabs of cement foundation in many cases,” he adds.

A notice on the Alabama Department of Insurance website notes that Alabamians have filed an estimated 65,000 insurance claims related to the storms.

Ridling says in the notice that he expects a second wave of claims to be filed next week. "With some areas just reopening, it is likely that people will wait through the weekend, and claims will spike again...," he says.

AIR says its insured loss estimate does not include loss adjustment expenses.