Tornadoes driven by warm spring-like conditions have killed at least three people and caused extensive damage across the US Midwestern states.
On Tuesday night, nearly 45 million Americans were hit by the severe weather which poured rain and hail on states between Arkansas and Ohio.
One person was killed in the city of Ottawa, Illinois, where more than 100 homes were destroyed.
Another person was confirmed killed by a tornado in Perry County, Missouri.
Authorities say the man died when the car he was driving was blown off the road. His passenger was not harmed.
In Crossville, Illinois, a 71-year-old man was killed and his wife was injured by a suspected tornado.
The National Weather Service received unconfirmed reports of 22 tornadoes across five states, with many occurring after dark on Tuesday night.
A cold front is predicted to move into the area on Wednesday, shifting the storm threat to the Southeastern US.
In Ottawa, one man was injured and another killed when a tree branch fell on them while they were outside “performing some work task”, according to Captain Dave Gualandri of the Ottawa police department.
The nearby LaSalle County Nursing Home in Ottawa was also struck, causing some residents there to suffer minor injuries.
About 50 homes were damaged in the nearby village of Naplate, according to Fire Chief Jon Nevins.
More than 100,000 people awoke without power on Wednesday, as emergency crews struggle to repair downed power lines under the threat of more storms.
Near the small town of Perryville, Missouri, about 10 homes were heavily damaged by the high winds, which also tossed cars and trucks off Interstate 55.
The highway has been closed due to storm damage.
Hail fell in Missouri and Wisconsin, producing three-inch (7.5cm) pieces in some places.
In White County, Arkansas, 10-15 people were injured, according to the state department of emergency management.
Forecaster Ariel Cohen with the Storm Prediction Center in Norman, Oklahoma, says the storm system is being driven by sunshine warming the air in the region, and roiling the atmosphere.
Tornadoes kill three across US Midwest