Estimates of insured losses from tornadoes and severe storms that struck the U.S. Midwest and Southeast continue trickling in but have yet to form a clear picture of how many billions of dollars in damage the storms inflicted.

Catastrophe modelers EQECAT Inc. and AIR Worldwide Corp. each predicted total insured losses resulting from the April storms would fall between $5 billion and $7 billion.

Last week, Northbrook, Ill.-based Allstate Corp. said it expects its losses from the violent weather to reach $1.4 billion, the vast majority due to storms that ripped through the Southeast on April 25-28.

In its first-quarter 2011 earnings statement, Boston-based Liberty Mutual Group Inc. said total industry losses for April could range from $10 billion to $15 billion.

“It's obviously a wide range, but we have a high degree of confidence that that's the magnitude,” Ted Kelly, chairman and CEO of Liberty Mutual, said during a first-quarter earnings analyst call. He said Liberty Mutual's share of the storm losses in April could be as high as $450 million.

Germany-based Munich Reinsurance Co. said its burden from the storms could reach up to $212 million.

In North Carolina, more than 6,640 homes and 112 businesses were destroyed or damaged during April 16 storms, and insured losses for the month are likely to be as high as $997 million in the state, said a spokesman for the Des Plaines, Ill.-based Property Casualty Insurance Assn. of America.

The National Weather Service received 875 eyewitness reports of tornadoes last month, one-quarter of which were reported April 27. That day, storms in Alabama, Mississippi and Tennessee killed approximately 350 people and caused up to $2 billion in insured losses in Alabama alone.

How commercial properties will factor into the insured loss estimates remains unclear.

So far, Columbus, Ohio-based Nationwide Mutual Insurance Co. said it has received more than 2,700 claims for commercial property damage caused by the April storms. In Mississippi, as many as 135 businesses were damaged or destroyed.

As rampant as the devastation was, industry observers say the storms will have little, if any, impact on rates in the direct insurance or reinsurance markets. But when tethered to catastrophes in Japan, Australia and New Zealand, the picture changes, experts say.

Lara Mowery, managing director at New York-based reinsurer Guy Carpenter & Co. L.L.C., said the April U.S. storms could contribute to a reinsurance market “in transition.”

While rates for January U.S. catastrophe reinsurance renewals were down 6% to 10% and were expected to remain soft, that was before the disaster in Japan. Instead, Ms. Mowery said, April 1 reinsurance renewals reflected a “flat to slightly up reinsurance environment.”

“In terms of a bigger picture, (the storms) are one more event to add to the list,” Ms. Mowery said. “By themselves, they wouldn't have had any broad impact.”