The coldest weather to grip North America in decades, caused by a blast of air from the so-called polar vortex, is spreading south and east across the continent.
The bone-chilling temperatures shattered records Tuesday, with the mercury plunging to minus 27 degrees Celsius in Chicago and to minus 14 degrees Celsius in Georgia, making it the coldest day the southeastern state has seen in 44 years.
Montana recorded the coldest temperature though with the wind chill making it feel like minus 53 degrees Celsius.
Schools have been shut down, people urged to stay indoors, and road, rail and particularly air travel turning into a nightmare with more than 4,300 flights cancelled, nearly half of those in Chicago.
More than a dozen deaths have been linked to the dangerously low temperatures.