Areas affected: Alabama, Florida, Georgia, Louisiana, Mississippi, Tennessee
Insured losses (then): $41.1 billion
Insured losses (in 2011 dollars): $47.5 billion
Disaster insurance tip: Most homeowners insurance policies exclude floods. Check yours. The National Flood Insurance Program offers supplemental flood coverage to anyone in the U.S. The average flood premium is about $600 a year. Basic policies for low- to moderate-risk areas start at $129.