Parts of the United States are facing what could be the coldest temperatures in years. The cold weather and snowstorms have forced the cancellations of thousands of flights, while schools have been closed in some states.
Weather forecasters in the United States said the cold temperatures, which have been caused by something known as a polar vortex, could be set to break decades-old records.
"It's just a dangerous cold," said Butch Dye, meteorologist with the US National Weather Service.
Weather forecasters said they expected the mercury to drop to as low as -35 degrees Celsius (-32 Fahrenheit) in North Dakota and -26 in Chicago, Minneapolis and Indianapolis.
Gusty winds make matters worse, and forecasters said this could lead to "wind-chill" temperatures as low as -50 Celsius.
Schools were ordered closed in Chicago and a number of other cities in the American Midwest on Monday, while the mayor of Indianapolis upgraded the local travel warning to "red," which means nobody is allowed to drive except for emergencies or to seek shelter.
The cold snap has also led to the cancellations of more than 3,000 flights in and out of the United States, according to the flight tracker FlightAware.com.
Officials have warned that at such low temperatures frostbite and hypothermia can set in within a matter of minutes.
"I have seen frostbite occur through clothing," Douglas Brunette, an emergency room doctor in Minneapolis told the Associated Press. "It's not enough just to be covered. You need clothes made for the elements. You need to repel the wind."
The outbreak of freezing weather comes on the heels of a huge weather system that hit the US Midwest and Northeast in the first days of the new year. At least 16 people have died from storm-related causes.
Forecasters said the polar vortex, which happens when freezing air streams southward from the Arctic Circle to Canada and the United States, would likely continue until the middle of the week and could get worse before it gets better.
pfd/se (AP, dpa, AFP)