北美寒潮正逐渐减弱The deep freeze that has left people in North America shivering for days, shattering century-old temperature records, is loosening its icy grip.数日来令北美人民打着寒颤、刷新百年最低气温记录的寒潮已经开始衰退。 The mercury is rising in the US Midwest and East, which has bor ne the brunt of the so-called polar vortex（极地漩涡）, 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. 'Dramatically warmer' The US National Weather Service predicted "a much-anticipated warm up" for much of the eastern US on Wednesday. The US Midwest - which experienced -37C (-35F) in recent days - also warmed slightly, but still faced temperatures 15 to 25 degrees below average. Atlanta, Georgia, returned to a more temperate 5C (42F) on Wednesday following a record low of -14C (6F) a day earlier. New York City topped -5C (22F) on Wednesday, after shattering a 118-year-old low temperature record with -15C (4F) on Tuesday. Temperatures in parts of North America plunged so low this week that they eclipsed readings recently recorded on the Red Planet by the Mars Rover. Even Alabama's top official was not immune to the e xtreme cold. Governor Robert Bentley faced an estimated $50,000 in damage after a water pipe froze and burst in the attic of his home in Tuscaloosa. In Canada, meanwhile, a 70-year-old Ontario man is recovering in hospital after being buried in a snowdrift in his vehicle for nearly 24 hours, reports CBC.
