Chicago (AP) -- Snow-covered roads, high winds and ice were creating dangerous driving conditions from Missouri to Delaware on Sunday ahead of a "polar vortex" that'll bring below-zero temperatures not seen in years to much of the nation in the coming days, likely setting records.
Several states in the Midwest were being walloped with up to a foot of new snow, and residents shoveled out and stocked up on groceries before bitterly cold temperatures set in overnight.
Five to 7 inches fell overnight in the Chicago area, while 8 to 10 inches was expected to fall in central Illinois, Indiana and Michigan on Sunday, National Weather Service meteorologist Ed Fenelon said. Forecasts also called for several inches in western Tennessee and 1 to 3 inches in Kentucky.
The vortex, a counterclockwise-rotating pool of cold, dense air, will affect more than half of the continental U.S. starting Sunday and into Monday and Tuesday, with wind chill warnings stretching from Montana to Alabama. With it comes a startling forecast: 25 below zero in Fargo, N.D., minus 31 in International Falls, Minn., and 15 below in Indianapolis and Chicago.
In Chicago, temperatures were expected to fall throughout Sunday to about 11 degrees by 5 p.m., "and from there it will be a free fall for the rest of the night," with temperatures bottoming out around minus 15 overnight and likely setting a daily record, Fenelon said.
The biting temperatures already pushed into northern states Sunday morning. The National Weather Service reported temperatures in the 20-below range in northern Minnesota and Grand Forks, N.D. The coldest wind chill in Minnesota was minus 50 in Flag Island.
"It's just a dangerous cold," National Weather Service meteorologist Butch Dye in Missouri said Sunday morning.
In St. Louis, grocery stores sold out of the essentials before Sunday's weather onslaught.
"The problem is the bread is sold out. We're out of milk. We sold out of chips, chicken wings, some meats," Issa Arar of Salama Supermarket said.
Travel problems started early Sunday. In New York City, a plane from Toronto landed at Kennedy International Airport and then slid into snow on a taxiway. No one was hurt, though the airport temporarily suspended operations for domestic and international flights because of icy runways. Flights resumed around 10 a.m. EST.
About 1,200 flights had been cancelled Sunday morning at O'Hare and Midway international airports in Chicago, aviation officials said.
Mike Duell, with flight-tracking website FlightAware.com, said Saturday to expect delays and flight cancellations because of the cold temperatures.
"For some of them, they run into limitations on the aircraft. They're only certified to take off at temperatures so low so if they get into a particular cold front it can prevent them from being able to legally take off," he said.
Roads in Missouri, Indiana, Illinois and elsewhere were dangerous. Officials in Missouri warned that it was too cold for rock salt to be very effective.
"If it gets to the point where it's no longer safe, we will consider suspending operations," said Missouri Department of Transportation spokeswoman Marie Elliott.
It hasn't been this cold for almost two decades in many parts of the country. Because of that, medical experts are reminding people that frostbite and hypothermia can set in quickly at 15 to 30 below zero, and it's key to be dressed for the temperatures.
"They have to wear a hat, they have to have face protection," said Dr. Brian Mahoney, medical director of emergency services at Hennepin County Medical Center in Minneapolis. He said layers of dry clothing are best.
Southern states are bracing for possible record temperatures, too. Meteorologists in central and north Georgia say temperatures could drop into the single digits by Tuesday, accompanied by wind chills as low as 15 below zero. Officials in Alabama said the cold temperatures - in the single digits - could negatively impact exposed vegetation and livestock.
Elsewhere, Minnesota has called off school Monday for the entire state - the first time in 17 years - as well as the Wisconsin cities of Milwaukee and Madison. Other places are likely to follow.