People have been forced to abandon homes and businesses
At least 13 people have died and hundreds of homes have been evacuated as a result of rains and floods in the central United States.
Three days of heavy rain have prompted the National Weather Service to issue flood and flash flood warnings from Texas to Pennsylvania.
Worst hit are Missouri, Arkansas, Illinois, Ohio and Kentucky, with about 30cm (12 inches) of rain in some areas.
The US coast guard has helped rescue
people trapped in their homes and cars.
Six deaths were linked to the flooding in Missouri - including that of a 19-year-old man swept two miles (3.2km) downstream in a flooded creek.
Five people died in a road accident in heavy rain in Kentucky and a 65-year-old Ohio woman drowned in her home.
In southern Illinois, two bodies were found after floodwaters swept a truck off a rural road.
An estimated 300 houses and businesses were flooded in Piedmont, Missouri and the Meramec River was threatening towns outside St Louis.
Missouri Governor Matt Blunt, a Republican, has asked for federal help for 70 Missouri counties and the City of St Louis as a result of flooding and severe weather.
The US Coast Guard has joined the emergency operations on rescue missions in south-east Missouri.
"The current flooding conditions are causing great hardships on Missourians who are being evacuated from their homes, rescued from trapped vehicles, or are separated from their families," Governor Blunt said.
"I have directed all state resources to be available to assist in the rescue and recovery efforts in the affected areas."
Ohio rescue workers have been helping rescue people from cars swamped by the flooding.
"The biggest problem has been people driving into floodwater," Frank Young, emergency management director in Warren County told the Associated Press news agency.
"There are a lot of stupid people. When that sign says 'Road closed, high water', that's what it means."