Freezing temperatures have gripped large parts of the US, as the midwest and northeast brace themselves for another blast of dangerous winter weather.
A new round of Arctic air will bring potentially record low temperatures in areas from Montana to Michigan starting this weekend, with the extremely cold air pushing eastward and blanketing the northeast.
Blizzard conditions are expected in the Central Plains and Great Lakes regions. Pittsburgh could see temperatures about -24C by the early hours of Tuesday. Chicago could be about negative -29C.
"Incredibly, it may feel as cold as negative 50 to negative 60 (-45C to -51C) on Sunday night over sections of the north-central states," the National Weather Service said.
In those conditions, frost bite can set in on exposed skin within five minutes, forecasters warned.
Minnesota Governor Mark Dayton has ordered all public schools in the state closed on Monday to protect children from dangerously cold weather.
Chicago schools will be open tomorrow despite the cold but officials, in a statement, advised parents to "use their own discretion in deciding whether to send their child to school."
The storm comes on the heels of a massive winter weather system that slammed the Midwest and northeastern United States just after New Year's Day, causing several deaths, grounding thousands of flights and forcing the closure of schools and government offices.
Snow and icy conditions have snarled air travel in recent days, and delays and cancellations continued to cause headaches for travellers.
A total of 993 flights had been cancelled across the United States and 4,211 flights were delayed, with Chicago's O'Hare International Airport and Newark Liberty International Airport in New Jersey among the hardest-hit, according to tracking firm FlightAware.com.
Airlines cancelled more than 180 flights at O'Hare, according to the airport.
Boston was especially hard-hit by the first major storm of 2014, logging about 18 inches of snow on Friday, while some towns north of New England's largest city saw close to 2 feet of accumulation.
Police and the National Guard rescued 10 people from five beachside houses in Duxbury, Massachusetts, where flooding occurred, according to the Boston Globe.
But life has begun to return to normal in Boston. The city lifted its snow emergency at 5pm yesterday.