The Cedar river reached a peak of 31.8ft (9.7m) on Friday
Thousands of people in the US state of Iowa have been urged to leave their homes because of rising river levels.
A hospital in the city of Cedar Rapids was flooded and its patients evacuated after the Cedar river burst its banks and swamped more than 400 streets.
Iowa Governor Chet Culver has declared 83 of the state's 99 counties to be disaster areas and said that nine rivers are at, or above, record levels.
The floods have also destroyed much of the Midwest's corn and soybean crops.
The damage has helped push prices for the foods to record levels this week. Wheat, oats and rice production has also been affected.
One of the worst flooded areas in Iowa has been Cedar Rapids, the state's second largest city with a population of 124,000, where at least 438 city centre streets were inundated by rising water from the Cedar river and a railway bridge collapsed.
More than 170 patients from the Cedar Rapids hospital had to be evacuated after water from the river began to seep into its lower floors, where an emergency generator was located.
"They proactively and preventatively started evacuation basically guessing on the fact they were going to lose power," Dustin Hinrichs of the Linn County Emergency Operations Centre said.
The river level would reach a peak of 31.8ft (9.7m) on Friday, 11.63ft (3.53m) higher than it reached during the 1993 flood, considered the worst in recent history, said a spokesman for the city's fire department, Dave Koch.
In the state capital, Des Moines, officials issued a voluntary evacuation order for much of the city centre and other areas along the banks of the Des Moines River.
"We think that the levels are going to be at or very close to levee height," Mayor Frank Cownie said. "We're working like crazy to protect our property."
Flooding has also swamped parts of Minnesota, Illinois, Wisconsin, Missouri, Kansas and Indiana. So far, officials in Indiana have reported three flood-related deaths and at least two deaths in Iowa.