(Reuters) - Rain-swollen rivers rose across Missouri on Wednesday with widespread flooding forcing the evacuation of hundreds of people, closing parts of a major interstate highway and threatening to wash out scores of structures.
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, Governor Jay Nixon said.
Nixon called the flooding "very historic and dangerous" and urged motorists not to drive into moving water. A dozen of the deaths in Missouri were due to people driving into flooded areas, Nixon told CNN on Wednesday.
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.
News video showed homes and business already surrounded by water almost up to their roofs in Missouri while crews in other areas put up sand bag barriers in hopes of keeping out floodwaters. Nixon has called out the National Guard to help in his state.
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.
At the confluence of the Mississippi and Missouri rivers, about 20 miles (32 km) north of St. Louis, residents of the towns West Alton and Arnold were told to evacuate on Tuesday.
The U.S. Coast Guard closed a 5-mile (8 km) 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 60 miles (100 km) south of St. Louis would crest at 49.7 feet (15.1 meters) 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 Center, 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.
Governor Bruce Rauner on Tuesday issued a state disaster proclamation for seven counties to help with response and recovery.
(This story has been refiled to correct typo in "moving" in third paragraph)
(Reporting by Victoria Cavaliere in Los Angeles and Mary Wisniewski in Chicago; Editing by Bill Trott)