Private market insured losses from the tornado outbreak in America between April 25 and 28 2011 will range from $3.5bn and $6bn, according to estimates from Risk Management Solutions (RMS).

The figures represents insured losses from states including Alabama, Georgia and Tennessee.

The estimate includes losses from personal, commercial, auto, and industrial lines of business.

Alabama, the worst affected state, experienced the majority of the strong to violent tornadoes and accounted for approximately 70% of the overall loss.

A total of three EF5 and 11 EF4 tornadoes have been confirmed from the outbreak, the majority of which touched down in Alabama.

The EF-4 rated Tuscaloosa/Birmingham tornado that passed through Greene, Jefferson, and Tuscaloosa counties in Alabama on Wednesday, April 27, accounts for nearly 40% of the RMS total insured loss estimate.

“This tornado outbreak is set to become one of, if not the, costliest severe convective storm event in U.S. history,” said Matthew Nielsen, product manager at RMS.

“A key contributor to the extent of damage was the exposure within the tornado touchdown area.”

For more, read our analysis: US tornado comes at the worst time.