The eastern half of the U.S. shivered Monday as a dangerously cold whirlpool of dense air known as a "polar vortex" threatened to break decades-old records and freeze exposed skin within minutes. School closures and flight delays rippled across the country in response to the deep freeze.
The National Weather Service said the temperature sank to 16 degrees below zero on Monday morning at Chicago's O'Hare International Airport, a record low for this date. The wind chill made it feel far colder and the temperature was continuing to fall. Much of the nation is also bracing for record-breaking temperatures.
In New York City, the temperature was expected to drop sharply from about 52 degrees to about 10 degrees overnight as the arctic air moved in.
The polar vortex is also expected to drive down temperatures in more than half the continental U.S. on Monday and Tuesday, with wind-chill warnings stretching from Montana to Alabama.
Wind chills in some areas — what it feels like outside when winds are factored in — could drop to the minus 50s and 60s. Northeastern Montana was warned of wind chills up to 59 below zero.
It hasn't been this cold for almost two decades in many parts of the country. Frostbite and hypothermia can set in quickly at 15 to 30 below zero.
"It's just a dangerous cold," National Weather Service meteorologist Butch Dye in Missouri told The Associated Press.
It was 5 degrees at kickoff Sunday afternoon at a sold-out Lambeau Field in Green Bay, Wisc., for an NFL playoff battle between the hometown Packers and the San Francisco 49ers — one of the coldest games ever played.
"We suited up, we brought all the snowboarding gear we use ... and added to it," said 49ers fan Jeff Giardinelli of Fresno, Calif. "Without the wind, which isn't here yet, we're good. When it gets windy, we'll be ready for it."
Several Midwestern states received up to a foot of new snow Sunday. The National Weather Service said snowfall at O'Hare International Airport in Chicago totaled more than 11 inches as of 6 p.m. Sunday — the most since a February 2011 storm.
The St. Louis area had about a foot of snow, and northern Indiana had at least 8 inches.
Officials closed several Illinois roadways because of drifting snow and warned residents to stay inside. Roads in the Midwest were particularly dangerous, and officials in Missouri said it was too cold for rock salt to be very effective.
Indiana officials declared a state of emergency for its northern counties, where the wind chill was expected to drop to 45 degrees below zero.
Authorities also urged people to check on elderly and disabled relatives and neighbors.
Lorna West, a 43-year-old student and consultant from Columbus, Ohio, told AP she doesn't believe people unaccustomed to such weather are ready for what's coming.
A Chicago native, she said thermal underwear, lots of layers and "Eskimo coats" with zipped hoods to block the wind were the norm growing up.
"And don't go out if you don't have to," she said.
In Michigan, residents jammed stores to stock up on supplies.
"I made my husband go grocery shopping last night," Kim Tarnopol, 46, of the Detroit suburb of Huntington Woods told AP. She was picking up cold medicine Sunday for her daughter Emma at a drugstore in nearby Berkley, Mich.
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 suspended operations because of icy runways.
About 1,300 flights were canceled Sunday at O'Hare and Midway airports in Chicago, aviation officials said, and there were also cancellations at Logan Airport in Boston, Tennessee's Memphis and Nashville airports and Lambert Airport in St. Louis.
School was called off Monday for the entire state of Minnesota — a first in 17 years — as well as in cities and districts in Wisconsin, Illinois, Indiana and Iowa, among others.
Chicago Public School officials reversed course late in the day Sunday, canceling classes for Monday ahead of the expected bitter-cold temperatures. The change in plans came amid criticism from the Chicago Teachers Union; officials say they made the decision after they re-evaluated the situation. Schools CEO Barbara Byrd-Bennett said closing is "in the best interest of our students."
Southern states are bracing for possible record temperatures, too, with single-digit highs expected Tuesday in Georgia and Alabama.
Temperatures are expected to dip into the 30s in parts of Florida on Tuesday, raising fears of damaged crops. But Andrew Meadows, a spokesman for Florida Citrus Mutual, an industry clearinghouse, said it must be 28 degrees or lower for four straight hours for fruit to freeze badly.
In western Kentucky, which could see 1 to 3 inches of snow, Smithland farmer David Nickell moved extra hay to the field and his animals out of the wind. He also stocked up on batteries and gas and loaded up the pantry and freezer. A 2009 ice storm that paralyzed the state and knocked out power to hundreds of thousands of people is fresh in his mind.
"We are hoping this isn't going to be more than a few days of cold weather, but we did learn with the ice storm that you can wake up in the 19th century and you need to be able to not only survive but be comfortable and continue with your basic day-to-day functions," Nickell told The Associated Press.
Al Jazeera and The Associated Press