The deep freeze that has left people in North America shivering for days, shattering century-old temperature records, is loosening its icy grip.
The mercury is rising in the US Midwest and East, which has borne the brunt of the so-called polar vortex, but was still below freezing in many areas.
At least 21 people have died since Sunday as a result of the weather, and more than 11,000 flights were grounded.
US natural gas usage hit an all-time record in the US to meet heat demands.
Forecasters predicted weather would return to normal across much of the US in the coming days, after 50 US cities set new record low temperatures on Tuesday.