Most of the nation is waking up to a blast of arctic weather Thursday morning after temperatures plummeted overnight.
From below zero temperatures in the upper Great Plains to ice in Texas and Arkansas, forecasters are calling it the coldest weather system to hit the United States since the 1990s.
Slick and icy roads are making driving conditions dangerous, causing hundreds of accidents. Fatal crashes have been reported across several states, with at least five of them in Minnesota.
"People started going into the ditch, losing control of their vehicles," Sgt. Carrie Johnson, with the Wisconsin State Patrol, said.
But the dangerous conditions aren't stopping postal workers in northern Minnesota, even after two feet of snow.
"It's not always the most enjoyable time of year when we have bad weather conditions, but we all try to stay in the Christmas spirit," postal carrier Mike Sylvester, in Duluth, Minn., said.
Forecasters say a new storm is expected to develop Thursday in New Mexico and west Texas. The Texas Department of Transportation said it's prepared.
"We already have equipment and manpower strategically placed throughout the district, and they're in areas where they can be quickly and easily mobilized when the time comes," Texas Department of Transportation spokesman Ryan LaFontaine.
Unfortunately the storm is expected to hit just in time for the Dallas Marathon. Runners say they're not sure they're prepared for the wintry conditions.
"I don't run on ice, being from Houston!" Rachel Williams, a marathon runner from Houston, said.
Widespread power outages are expected as the storm continues south and then east.
The National Weather Service warned that heavy ice and snow accumulations will likely bring down power lines, leading to outages that could take days to repair.
Meanwhile, doctors are warning people to be on the lookout for frost bite, especially in areas where the temperature is dropping far below freezing.
For example, in places like Bismarck, N.D., where the wind chill has dropped to 40 below, frost bite can set in after only 10 minutes.