Year of Misfortune: Top 12 Billion-Dollar U.S. Disasters

By Tom Randall - 2011-12-21T20:11:59Z

Photograph by Nati Harnik/Ap Photo

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#7 La Nina Tornadoes

Fifty-nine tornadoes swept through central and southern states on April 8-11, including at least 17 in Iowa. The biggest tornado was an EF4 in the city of Pocahontas. Damage exceeded $2.2 billion. People were able to take cover and while many were injured, no one died.

This year's disasters are partly attributable to a strong La Nina -- a system of cooling winds over the equatorial Pacific. The weather pattern was blamed for distorting the usual path of jet stream winds that cross the U.S., setting up violent clashes between colder weather from the north and warm storm systems from the south.

Jason Mauch (center) carries a basket from what remains of his house in Mapleton, Iowa. More than half the town's homes and businesses were damaged or destroyed.

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