To the north, ice and snow Wednesday left thousands of homes and businesses in Minnesota and South Dakota without power. Forecasters said more heavy wet snow was to come Thursday.
The most violent weather was centered near the St. Louis suburb of Hazelwood late Wednesday. Downed trees crushed several homes. Street signs lay scattered across rainy streets in the aftermath of the storm.
Hazelwood Mayor Mike Robinson told The Associated Press that about two dozen homes were damaged and that trees were down throughout the city. He said emergency workers had checked all the homes and that no serious injuries had been reported.
Hazelwood resident Ellen Knop said her home was badly hit.
"The garage is gone and I'm pretty sure the front porch is in the family room," Knop told The St. Louis Post-Dispatch.
Butch Dye, a hydrometeorological technician with the National Weather Service in St. Louis, Mo., said crews would assess the damage Thursday.
"We won't be able to confirm whether it was a tornado until teams get out there," Dye said.
Ameren Missouri said about 27,000 customers in the St. Louis area were without power early Thursday morning. Missouri Gov. Jay Nixon declared a state of emergency.
A tornado was reported to have touched down near Botkinburg in north-central Arkansas, said John Robinson, the warning coordination meteorologist at the National Weather Service office in North Little Rock. Four people were injured.
In Minnesota, Gov. Mark Dayton said the weather was taxing the resources of local and county governments, and he issued an executive order activating the National Guard.
The town of Worthington was using backup diesel generators to power sections of the city at a time, public utilities manager Scott Hain told Minnesota Public Radio. Roughly a quarter to a third of the city of about 13,000 people was without power at any given time, he said.
"With the generation that we have available, we are conducting rolling blackouts through the community," Hain said. "From what we're hearing from the folks that own the transmission that's down right now, is we expect that we'll be operating under this same scenario at least through the rest of today and possibly into tomorrow as well."
The National Weather Service forecast another 8 or 9 inches of snow in southeastern Minnesota on Thursday, with up to 14 inches across the south of the state, including the Twin Cities, St. Cloud, Willmar and Mankato.
Utilities in South Dakota were struggling to restore power to more than 20,000 customers still in the dark after the first wave of heavy snow hit the state early Wednesday.
Emergency crews meanwhile tried to reach isolated tribal members after deep snow blocked roads to rural communities on the Pine Ridge Indian Reservation. Tribal official Toni Red Cloud told the Rapid City Journal that the crews were focusing on reaching those with pressing medical needs such as dialysis patients.
More snow and strong winds were forecast for Thursday.
The weather service said the challenging weather could extend into flood-prone southeastern North Dakota, where about 3 to 5 inches of snow is expected through late Thursday.
One weather service meteorologist said the snow would not change the current flood forecast.
"Any additional precipitation at this stage in the game is not necessarily a good thing," said Peter Rogers in Grand Forks. "But we're not expecting that to have an immediate impact on the rivers either."
In Wisconsin, rain, ice and snow caused minor flooding Wednesday in areas including the Rock River at Afton and Newville, Crawfish River at Milford, Sheboygan River at Sheboygan, and Manitowoc River at Manitowoc.
Wisconsin Emergency Management spokesman Tod Pritchard said another wave of freezing rain could sweep across central Wisconsin from La Crosse to Green Bay from late Wednesday into Thursday. That rain could cause more flooding in the region.