Submerged roads and houses are seen after several days of heavy rain led to flooding, in an aerial view over Union, Missouri December 29, 2015. [Photo/Agencies]

At least 24 people have died in Missouri, Illinois, Arkansas and Oklahoma in flooding after days of downpours that brought as much as 12 inches (30 cm) of rain to some areas. Most of the deaths resulted from people driving into flooded areas.

In Eureka, Missouri, along the Meramec River, Mayor Kevin Coffey said a man was rescued from atop the cab of his pick-up truck after spending the night in a parking lot to watch over his gun shop business.

"This is 4 feet (1.2 meters) above the worst flood we ever had," Coffey said after helping to put sandbags around a school. "The town looks like one huge lake."

Historic floods on the Mississippi in 1993, 1995 and 2011 occurred during warm weather, after snow melts in the north. AccuWeather senior meteorologist Alex Sosnowski called it highly unusual to have heavy flooding in winter and said it could presage trouble for 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 that water standing more than a week could kill the soft red winter wheat crop. Export premiums for corn and soybeans were at their highest levels in weeks because of stalled barge traffic on swollen rivers.

2,500 HOGS DROWN

Livestock also has been hard hit. About 2,500 hogs drowned in an Illinois barn after a creek overflowed its banks, said Jennifer Tirey, a spokeswoman for the state's Pork Producers Association.

"There was no electricity and roads were impassable. It was just impossible to get to those pigs," she said.