At least six deaths were blamed on cold weather in U.S. southern Plains to the country's Northeast, where drivers face a grim commute Monday with ice and freezing rain making roads treacherous.
Roads in much of Oklahoma were considered slick and hazardous by the state Department of Transportation, with two sections of Interstate 40 being closed temporarily.
In Chicago, authorities said Sunday evening that poor weather and low visibility forced the cancellation of more than 400 flights at O'Hare International Airport.
Missouri Gov. Matt Blunt, who declared a state of emergency, also activated the Missouri National Guard to aid communities affected by the storm.
At Kansas City International Airport, about two dozen flights were canceled. At Lambert International Airport in St. Louis, 13 flights were canceled.
Another storm was forecast Monday night into Tuesday, but it was expected to clear out by Wednesday, Weather Service meteorologist Benjamin Sipprell said. Some communities reported ice as much as three-quarters of an inch (2.5 centimeters) thick, he said.