Parts of the United States could see record-breaking low temperatures as an Arctic chill brings more freezing weather to the US and Canada.
The stream of bitterly cold air is beginning to sweep down on the American mid-west, with termperatures in some places already minus 30 degrees Celsius.
Forecasters say a polar vortex - an Arctic blast - will bring with it sub-zero temperatures many Americans have never experienced before, the BBC reports.
Wind chill warnings have been issued for large swathes of the country - from Montanna to Alabama. The lowest temperatures are expected to hit North Dakota, Minnesota and Chicago.
Officials say the weather can be life-threatning and are urging people in the worst-hit areas only to make necessary journeys, warning that frostbite and hypothermia can set in after minutes in the cold.