The Arctic blast gripping much of the eastern US has begun to ease off. Winds dropped and the weather warmed slightly.
The change came a day after temperature records, some more than a century old, were shattered.
At least 21 people have been killed by the cold since Sunday. Five died after collapsing while shovelling snow, while several victims were identified as homeless people who either refused shelter or did not make it to a warm haven soon enough.
All 50 states saw freezing temperatures at some point on Tuesday. That included Hawaii, where it was -8C atop Mauna Kea, a dormant volcano.
In Atlanta, where a record low of -14C hit, the forecast was sunny and a more normal 5C.
The big chill started in the Midwest over the weekend, caused by a kink in the “polar vortex,” the strong winds that circulate around the North Pole.
The icy air covered about half the country by Tuesday. With the bitter cold slowing baggage handling and aircraft refuelling, airlines cancelled more than 2,000 flights on Tuesday, bringing the four-day total to more than 11,000.
Natural gas demand set a record, eclipsing the mark set a day earlier.
Across the south, records were shattered like icicles. Birmingham, Alabama, dipped to a low of -14C, breaking the record of -11.7C set in 1970.
The deep freeze dragged on in the midwest as well, with the thermometer reaching -24C overnight in the Chicago area.
More than 500 passengers were stranded overnight on three Chicago-bound trains which were stopped by drifting snow in Illinois. Food ran low, but the heat stayed on.
An estimated 190 million people in the US felt the icy blast, caused by a kink in the “polar vortex,” the strong winds that surround the North Pole.