(Reuters) - Missouri, Illinois, Arkansas and eastern Oklahoma braced for more flooding on Thursday as rain-swollen rivers, some at record heights, overflowed their banks, washing out hundreds of structures, leaving thousands of people displaced from their homes, and some 9.3 million people in areas under flood warnings.
At least 28 people have died in the region's flooding since the weekend, mostly from driving into flooded areas after storms dropped up to 12 inches (30 cm) of rain, officials said.
The days of downpours have pushed rivers in the U.S. Midwest to levels not seen in decades, the National Weather Service and local officials said.
The flooding has closed sections of Interstate 44 and Interstate 55, both major trucking routes, along with many smaller roads near rivers, Illinois and Missouri officials said on Thursday.
Freezing temperatures in the area in the coming days will cause some flooded areas to turn icy, adding to challenges, forecasters said.
Flooding has destroyed hundreds of homes and businesses and Southern states can expect the same as overflowing rivers push downstream toward the Gulf of Mexico, the National Weather Service said. Significant river flooding is expected for the lower Mississippi River into mid-January, the NWS said.
The NWS said the flood warning area covered 9.3 million people on Thursday, down from 12.1 million on Wednesday and 17.7 million on Tuesday.
Louisiana Governor Bobby Jindal has declared a state of emergency to prepare for flooding, and levee systems are being monitored daily.
“All that water’s coming south and we have to be ready for it,” Lieutenant Governor-Elect Billy Nungesser told CNN. “It’s a serious concern. It’s early in the season. We usually don’t see this until much later.”
Water rose to the rooftops of some structures in Missouri towns and two rivers west of St. Louis crested at historic levels, flooding towns, disabling sewer plants and forcing hundreds of residents from their homes.
Eureka, Missouri, Mayor Kevin Coffey said his town had not seen such bad flooding in 150 years and some of its oldest businesses have been damaged. The Mississippi is expected to crest in the small town of Thebes, Illinois, at 47.5 feet on Sunday, more than a foot and a half (46 cm) above the 1995 record, the National Weather Service said.
Thebes village worker Bobby White said some sewage pumps were shut down to avoid overloading and portable toilets had been supplied to affected areas. Most homes in the town, including his own, are on a hill and should be fine, he said.
“Most of the people at the bottom of the hill moved out years ago,” White said. “If [flooding] comes on the hill, all of Alexander County will be wiped out.”
Illinois officials have provided 800,000 sandbags to communities endangered by the Illinois, Sangamon, Iroquois and Mississippi rivers, said Patti Thompson, spokeswoman for the Illinois Emergency Management Agency.
Some evacuees stayed with family or friends or went to hotels, while others found refuge in Red Cross shelters set up in the area.
Rick Miller, U.S. property practice leader for Aon Risk Solutions, said it was too early to comment on possible damage costs. He said the majority of the impact will be to the National Flood Insurance Program.
Miller does not expect the flooding, as bad as it has been, to be a "significant insurance industry event" and said the insurance impact of Hurricane Sandy in 2012 was far greater.
(Reporting by Victoria Cavaliere in Los Angeles, Richa Naidu in Bengaluru, and Mary Wisniewski in Chicago; Editing by Janet Lawrence and Bill Trott)