If you haven’t read it already, the April edition of the Global Catastrophe Recap Report by Aon Benfield’s Impact Forecasting puts some numbers around the thunderstorm events that devastated parts of the United States last month.

According to the report, severe weather and flash flooding that caused extensive damage across more than 20 states in April will likely be the first billion-dollar economic loss event of 2014 attributed to convective thunderstorms.

At least 39 people were killed and 250 injured amid nearly 70 confirmed tornado touch-downs, which occurred across more than 20 states in the Plains, Mississippi Valley, Southeast, Midwest, and Mid-Atlantic.

Economic losses are set to exceed $1 billion, with insured losses minimally in the hundreds of millions of dollars, Impact Forecasting reports.

Another U.S. severe weather outbreak in April led to major damage in parts of the Plains, Midwest and the Mississippi Valley. The most significant damage was due to hail, as hailstones the size of softballs struck the Denton, Texas metro region.

Total economic losses were estimated at $950 million, with insured losses in excess of $650 million, according to the report.

In a press release Adama Podlaha, head of Impact Forecasting, says:

The recent outbreaks of tornadoes, large hail and damaging straight-line winds in the United States have emphasized the importance of historical data analysis for insurers and reinsurers when trying to forecast future losses.”

If you’re wondering how many convective thunderstorm events made the list of significant natural catastrophes in 2013, take a look at this slide from a presentation made by I.I.I. president Dr. Robert Hartwig at the National Tornado Summit in February.

It shows that thunderstorms accounted for six of the nine significant natural catastrophe events with $1 billion economic loss and/or 50 fatalities in 2013.