Bloated by melting snow and rain across the Upper Midwest, the Mississippi River rose out of its banks and strained against dikes Tuesday in four states, stopping Amtrak trains and chasing hundreds of people from their homes.

Contractors in Minnesota rushed to shore up a weakened earthen dam on a tributary of the Mississippi.

Hundreds of people had left their homes in low-lying riverside areas of Wisconsin and Iowa, and volunteers and prison inmates sandbagged homes along the Mississippi at Hampton, Ill.

Among those who evacuated was Rep. Ron Kind, who moved his wife and two children out of their home on French Island, near La Crosse, Wis. Water was 4 feet deep in the house.

"We were completely engulfed and surrounded by the Mississippi," the congressman said after a canoe trip to check on the house and his neighbors. The Mississippi was expected to crest 4 1/2 feet above the 12-foot flood stage at La Crosse on Wednesday — lower than predicted.

Just upstream, in Fountain City, the main highway remained closed. School officials postponed the prom scheduled for Saturday at the high school and called off classes through Thursday.

A 403-mile stretch of the Mississippi from Muscatine, Iowa, to Minneapolis was closed to boat and barge traffic. Nine counties in western Wisconsin were under a state of emergency and a disaster proclamation was posted for 10 Iowa counties.

The Mississippi rose above 23 feet at St. Paul, Minn., for the first time since the 1960s. Four city parks and the downtown airport for small planes were under water.

One man was missing after he and a companion drove past barricades onto a flooded highway near Minneapolis earlier this week.

At Appleton, Minn., contractors were sent to shore up the Marsh Lake Dam on the upper Minnesota River. The earthen dam had been weakened by erosion and battered by huge chunks of ice.

If the dam were to collapse, officials said, it could raise water levels downstream at Montevideo and Granite Falls by up to 1 1/2 feet. However, the river was already receding in both communities and local authorities said dikes should be able to handle any increase.

"We're going to be ready for this if it happens, and it may not happen," Granite Falls Mayor Dave Smiglewski said.

Amtrak suspended its Empire Builder train service between Minneapolis-St. Paul and Chicago because of high water on the tracks. Passengers were put on buses. About 200 people were affected Monday, said Amtrak spokesman Kevin Johnson. The Empire Builder runs daily in both directions between Chicago and Seattle and Portland, Ore.

Burlington Northern Santa Fe's main rail line from the Twin Cities to Chicago remained closed Tuesday because the Mississippi was over the tracks at several locations. A spokesman said trains were being rerouted but faced delays of up to 48 hours.

More than 200 of the 300 families living on Abel-Essman Island, in the Mississippi near Guttenberg, Iowa, abandoned their homes Monday and the only road to the island was closed when the water reached 19 feet, or 4 feet above flood stage. The river is expected to crest there Friday at about 21 feet.

Several Mississippi River communities in Missouri were keeping an eye on water levels but expected no serious damage. No flooding was expected in St. Louis because of levees, floodwalls and the city's geography, National Weather Service hydrologist Scott Dummer said.