East St Louis, Illinois: The worst Midwest flooding in 15 years eased on Saturday after the swollen Mississippi River crested in St Louis, but the toll was still rising as billions of dollars in damage to crops, communities and infrastructure were assessed.

Emergency workers at river levees and floodwalls feared more rain could swell river levels again and complicate recovery efforts. But the skies remained mostly clear and thousands of relief workers could finally exhale.

"It really is looking positive. The weather has cooperated and that's made a difference," said Maggie Carson, a spokeswoman for Illinois Emergency Management.

Thunderstorms seen for the northern Midwest in the next few days were expected to be scattered and pose no new threat.

The flooding and storms blamed for 24 deaths since May have caused billions of dollars in damage to the heart of the US grain belt, pushing corn and other food commodity prices to record highs and feeding fears of higher world food prices.

Bridges and highways have been swamped, factories shut down, water and power utilities damaged, and the earnings of railroads, farmers and myriad other businesses disrupted. Iowa and Illinois have been the hardest hit, but parts of Wisconsin, Minnesota, Indiana and Missouri have also been swamped.