As the Midwestern United States shivered through the region's lowest temperatures in two decades and forecasters warned that life-threatening cold was heading eastward, officials in Chicago and other districts said schools would be closed on Monday.
Icy conditions snarled travel across the Midwest and thousands of flights were canceled or delayed, days after the Northeast was hammered by the first winter storm of the season.
"The coldest temperatures in almost two decades will spread into the northern and central US behind an arctic cold front," the National Weather Service said on Sunday. "Combined with gusty winds, these temperatures will result in life-threatening wind chill values as low as 60 degrees below zero (Fahrenheit/minus 51 degrees Celsius)."
In weather that cold, frostbite can set in on uncovered skin in a matter of minutes, experts warned. Minnesota Governor Mark Dayton ordered all public schools in
the state closed on Monday to protect children from dangerously cold weather.
Chicago public schools followed suit - reversing an earlier decision - saying in a statement on its website that it would be dangerous for children to commute to school amid sub-zero temperatures and high winds.
The NWS said the widespread chill was a result of a relatively infrequent alignment of weather conditions, allowing the Arctic polar vortex to be displaced unusually far south.
"The weather pattern across North America right now is set up to be very favorable for the southward transport of Arctic air," said Bob Oravec, a National Weather Service meteorologist.
"It's not going to be long-lived," he added. "By the end of the week the temperatures will definitely start to moderate across the whole of the country."
Gloves, firewood and chips
The cold snap, which comes during the slowest time of the year for shopping, could benefit retailers as they get ready to replace winter merchandise on shelves with spring items in a few weeks.
"It's mostly going to be dry, bitter cold so any retailer that has inventory left over from the holidays - jackets, scarves, hats, gloves - they need to clear that," said Evan Gold, senior vice president at Planalytics, a weather consulting firm in Berwyn, Pennsylvania.
In Nashville, Tennessee, where temperatures were forecast to drop from about 56 F (13 C) in the afternoon to 8 F (-13 C)overnight, Bradley Hite's firewood sales company FirewoodNashville.com was struggling to keep up with demand.
"It's been a lot more business (in the last couple of days). Just a lot more people coming in and picking it up. It's not normal," he said.
In Clintonville, Ohio, Janine Dunmyre found her local grocery store stripped of staples including milk, eggs and juice - as well as some less-essential supplies.
"The chips aisle was decimated," she said. "Like everyone is planning to sit around for two days with snack food." Dunmyre said she has already made plans for her four children to stay home from school on Monday due to cold temperatures and ice on the roads.
"I'm concerned more about everything turning to ice, not how much snow we are or aren't suppose to get," she said. "Wet power lines iced over means no power."