CEDAR RAPIDS (Iowa) - OVERFLOWING rivers in Iowa and other Midwest United States states forced evacuations and disrupted the region's economy on Friday with fears of worse to come from fragile levees and more rain.

A Cedar Rapids hospital was flooded and evacuated its patients after a levee break on the Cedar River turned the downtown area into a shallow lake. Thousands were forced to leave their homes in the worst Midwest flooding in 15 years.

'I don't know how much damage is done,' said Ms Latrina Walker, huddled at a shelter with her four children. 'I'm just really scared right now.'

Rescuers in boats picked up people who were stranded or had had ignored warnings to leave.

Officials in Des Moines city urged residents living near the rising Des Moines River to evacuate.

'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.'

Iowa Governor Chet Culver said the damage to his state could cost billions of dollars. Scores of bridges spanning nine overflowing rivers have been swept away or weakened.

'I have real concerns about our agricultural sector. I have toured the state and seen the devastation to our crops,' Mr Culver said.

Iowa is usually the top United States corn and soybeans growing state and is a major producer of hogs and cattle.

Crop losses could spur price rises for everything from food to fuels, like corn-based ethanol, and play into growing fears of inflation threatening the already battered US economy.

The flooding led authorities to close the upper Mississippi River to barge traffic, and commerce on a 480km stretch of the most important US waterway may be shut down for weeks.

An epic 1993 Midwest flood swamped several cities in Iowa, Missouri and neighbouring states, killing 48 people and caused US$21 billion (S$29 billion) in losses.

Along with torrential rains, the Midwest has been struck by several tornadoes, adding to the highest US death toll from twisters in a decade. A tornado on Wednesday killed four teenage boys at a scout camp in western Iowa.

Other states swamped
Flooding has also swamped parts of Minnesota, Illinois, Wisconsin, Missouri, Kansas and Indiana. Officials in Indiana have reported three flood-related deaths.

Three deaths have been reported in Iowa.

'We've been in a flood fight pretty consistently for 10 days now,' said Mr Bret Voorhees, a spokesperson for Iowa Homeland Security and Emergency Management.

National Guard troops and prisoners have joined residents in Iowa to pile up millions of sandbags to raise or buttress weakened levees.

The Cedar River's anticipated crest was at least a dozen feet higher than the level reached in 1993 and had broken a 157-year-old record.

Power outages affected 27,000 Iowa homes and businesses, with several grain and meat processing plants shut down.

The Mississippi was expected to crest in St Louis in eight days at a level below the peak seen in the 1993 flood, which prompted buy-outs of many riverfront properties and the construction of higher levees and more secure flood walls.

Scores of highways across the region were closed by flooding, turning short trips into lengthy detours.

Farmers across the region hoped for a break in the parade of storms that have swamped thousands of acres of planted fields or prevented them from planting anything.

Corn rose to record highs for the seventh session in a row at the Chicago Board of Trade, and soybean meal prices soared to a 35-year high on concerns of processing plant shutdowns.

In Wisconsin, overnight storms caused rivers to rise further, forcing evacuations and rescues - some by World War II-era amphibious vehicles, called 'Ducks', that were diverted to rescue work from carrying tourists. -- REUTERS