Rain-swollen rivers rose across Missouri and Illinois on Wednesday, forcing the evacuation of hundreds of people, closing parts of a major interstate highway and putting scores of buildings underwater after days of unusual winter flooding that has killed 22 people.
Several major rivers, including the vital Mississippi, were poised to crest at record levels as the floodwaters gushed towards the Gulf of Mexico, the National Weather Service said, but parts of the area already are inundated.
News video showed homes and business with water almost up to their roofs in Missouri — and one cabin floating away — while crews in other areas put up sand bag barriers in hopes of keeping out water. Missouri Governor Jay Nixon called the flooding in his state "very historic and dangerous" and brought out the National Guard to help.
At least 13 people have died in Missouri since the weekend, when days of downpours from a massive winter storm system triggered the state's worst flooding in two decades. Seven people have died from flooding in Illinois and two in Oklahoma, officials said.
Almost all of the deaths in Missouri and Illinois have been caused by people driving into flooded areas and Nixon urged motorists not to drive into moving water.
As much as 30cm of rain fell over three to five days in parts of the region.
Past historic floods on the Mississippi in 1993, 1995 and 2011 all happened during warm weather, after snow melts up north. AccuWeather senior meteorologist Alex Sosnowski said it is highly unusual to have this kind of flooding in winter and more trouble could come in the spring.
"The gun may be loaded again for another major flooding event," said Sosnowski, who cited the El Nino weather pattern as the source of recent heavy rains. "You're not supposed to get this kind of heavy rainfall during the wintertime."
Agriculture experts said the floodwaters and heightened disease risk that they bring were a threat to the soft red winter wheat crop in the southern part of the Midwest. Export premiums for corn and soybeans were at their highest levels in weeks because barge traffic on the swollen rivers has been tangled.
The US flooding comes at the same time as historic flooding across northern England, including York and Leeds.
Several major rivers, including the Mississippi, and tributaries in Missouri and Illinois were poised to crest at record levels, the National Weather Service said, but parts of the region already are inundated.
Flood warnings stretch from eastern Oklahoma into southeastern Kansas, southern Missouri, central Illinois and parts of Arkansas, Tennessee, and the Florida panhandle, the NWS said. A total of 46 locations are experiencing major flooding.
While the rains have stopped for now, colder weather is setting in, which will make the cleanup more miserable, Sosnowski said.
At the confluence of the Mississippi and Missouri rivers, about 32km north of St. Louis, residents of the towns West Alton and Arnold were told to evacuate on Tuesday. About 400 residents and businesses in the town of Pacific also have evacuated, said emergency manager Dian Becker.
"It will be the worst on record — that's what they tell us for later this evening," Becker said.
The US Coast Guard closed a 8km stretch of the Mississippi near St. Louis on Tuesday to all vessel traffic due to hazardous conditions.
The National Weather Service forecast the Mississippi River at the Chester, Illinois, river gauge about 100km south of St. Louis would crest at 15.1 metres on Friday — matching the 1993 record.
The floodwaters have forced the closure of roadways and highways, including multiple sections of Interstate 44, a major highway that runs from western Texas to St. Louis, the Missouri Department of Transportation said on Wednesday.
Sewage has been flowing into the fast-rising Meramec River near St. Louis since Monday, when floodwater disabled a sewer treatment plant, the St. Louis Post-Dispatch reported.
In Illinois, some inmates were moved out of the Menard Correctional Centre, a maximum security prison on the banks of the Mississippi River, and sandbags and drinking water were prepared in anticipation of flooding in lower level cell blocks, Illinois officials said in a statement.
