A powerful winter storm has barrelled toward Chicago, threatening to snarl the evening commute with heavy snow, ice and winds while leaving nearly all of the US Plains buried in its wake.
Blizzard conditions in Oklahoma, Texas and parts of Kansas, which were still digging out from a winter storm last week, shut highways and were blamed for two deaths.
Dumping up to 43cm of snow on Amarillo, Texas, and whipping Kansas City, Missouri, with winds of up to 48kmh, the storm continued its northward march.
It was headed for Chicago and Detroit by late afternoon, bringing with it as much as 15cm of snow, CNN reported.
Highways in the Texas and Oklahoma panhandles and parts of Kansas were closed because of heavy and drifting snow that cut visibility and forced flight cancellations at airports across the region.
A man was killed when his car slid off Interstate 70 in Sherman County, Kansas, near the western border, Governor Sam Brownback said.
And in northern Oklahoma, one person died when the roof of a home partially collapsed in the city of Woodward, said Matt Lehenbauer, the city's emergency management director.
"We have roofs collapsing all over town," said Woodward Mayor Roscoe Hill Jr. "We really have a mess on our hands."
Tornado watches are in effect from the Florida Panhandle to South Carolina, CNN said.
Some 17 inches of snow fell near Amarillo, Texas, according to the National Weather Service.
Other areas in the Texas Panhandle reported more than a foot, and Governor Rick Perry activated Texas military forces to be ready to respond to calls for assistance.
Visibility was near zero on some roads around Amarillo, said Paul Braun, a Texas Department of Transportation spokesman.
In Oklahoma, a state of emergency was declared for 56 of 77 counties, with the northwestern part of the state hit hardest. All highways in the Oklahoma panhandle were closed because of blizzard conditions.