Powerful storms swamp U.S. Midwest, spawn tornadoes

CHICAGO (Reuters) - Heavy rains caused flooding that forced hundreds of evacuations in Indiana, and a tornado raked Chicago's suburbs on Saturday as violent thunderstorms pummeled the already soggy U.S. heartland, authorities said.

The U.S. Coast Guard was called out to help rescue stranded homeowners and motorists, and near-record flooding was forecast for rivers and creeks in western and central Indiana.

"We are getting a lot of rain and water. There are a lot of roads that are impassable. We are urging people to sit tight and stay off the roads," said John Erickson of Indiana's Department of Homeland Security.

Some roads and highways were inundated and part of Interstate 70 had washed away, Indiana authorities said.

No one had been seriously injured in the flooding but Indiana Gov. Mitch Daniels declared an emergency in 10 more counties, added to the 41 counties declared earlier.

Some dams were in jeopardy, according to local media reports, following the latest round of heavy spring storms that have delayed farmers' planting schedules in several U.S. heartland states.

In Illinois, Saturday's storms were accompanied by at least one tornado that skipped across suburbs and farm fields South of Chicago.

The twister ripped roofs off several homes and apartment buildings, toppled semi-trailer trucks and tore down power lines, authorities said.

At least one person was injured and some 29,000 households were without power.

"We've had some reports of houses destroyed," said Andrew Krein of the National Weather Service.

Tornadoes also struck in Iowa and Wisconsin, capping a season that has seen a parade of storms spawning tornadoes, hail and destructive winds. According to the weather service, 112 people have died in tornadoes since the beginning of the year, the most in the United States in a decade.

(Reporting by Andrew Stern and Doris Frankel; Editing by Chris Wilson)