How cold is it?
It's so cold, even polar bears and penguins were being kept indoors Monday.
Anana, the lone polar bear at the Lincoln Park Zoo in Chicago, has never grown the thick layer of fat that bears in their native Arctic develop to insulate themselves against winter temperatures that can range as low as -50 degrees F, zoo spokeswoman Sharon Dewar said. So when temperatures plunged well into the negative range in Chicago, Anana stayed in a 40ish-degree habitat, Dewar said.
"In the wild, they would seasonally eat seals and fatten themselves up with that blubber," Dewar said. But zookeepers "don't feed them seals or fatten them up," she said.
And at the National Aviary in Pittsburgh, both bald eagles and African penguins "who are used to temperate climates" were taken off exhibit until the weather warms up, the facility reported.
Chicago saw a record low of minus 16 (minus 27 C) on Monday. The day's high was minus 11, with a windchill of minus 34. It's part of an Arctic blast that plunged deep into the central United States on Monday, leaving Nashville, Tennessee, 40 degrees colder than Albany, New York; Memphis 20 degrees colder than Anchorage, Alaska; and Atlanta colder than Moscow -- Russia or Idaho, take your pick.
The bitter cold that a "polar vortex" is pushing into much of the United States is not just another winter storm. It's the coldest in 20 years in many areas. The South was downright balmy compared to the Great Lakes region, where temperatures hovered in the negative 20s -- before wind chill, which dropped temps to the negative 40s and in places like Minneapolis.
Minnesota Gov. Mark Dayton ordered the state's roughly 2,000 public schools to close on Monday, the first such order since 1997. Many of those will stay closed Tuesday, including the three major districts around Minneapolis, where blowing snow shrouded bridges over the frozen Mississippi River.
"I've only been out of school four days ever, and today and tomorrow are two of the four days," said Graham Myers, who was going to a movie with several friends and his father.
Wind chills in the 40-below range can cause frostbite in a matter of minutes, the National Weather Service warned. But there were those who reveled in it.
"I love the cold. I'm one of those crazy cold-weather Minnesotans who just enjoys this," Robert Pettit told CNN as he took a walk on a work break. If properly dressed, "It's not so bad," he said.
"You dress up, put your mukluks on, get some gloves and a hat and you're set," Pettit said.
Freeze toll 15, mostly from accidents
Authorities have blamed a total of 15 deaths on the cold so far, 11 of them from traffic accidents.
But the the death of an Indianapolis woman found in her backyard early Monday "is believed to be weather-related," police spokesman Kendale Adams told CNN. A man in Wisconsin died of hypothermia, and an elderly woman with Alzheimer's disease who wandered away from her home in New York state was found dead in the snowy woods about 100 yards away, authorities there said.
In addition, hypothermia was a contributing factor in the death of a patient at University Hospitals Case Medical Center in Cleveland, hospital spokesman George Stamatis told CNN.
At the Salvation Army Harbor Light Center, a Minneapolis homeless shelter, Executive Director Bill Miller said 750 people came in off the street to spend the night Sunday.
"That's a record," he said. He said Harbor Light "will take in everybody, no matter if they've been drinking or whatever their issues might be."
Further south, the chill was less brutal but still nothing to dismiss. In Fairfield, Iowa, at minus 9, CNN iReporter Deborah Roberts called Monday "a good day to stay in and use the excuse it's too darn cold."
In Illinois, Gov. Pat Quinn called on state residents to stay off the roads and activated National Guard troops to help local authorities clear highways. In Chicago, Mayor Rahm Emanuel urged residents "to keep exercising good judgment and remain indoors if at all possible."
Welcome to 'Chiberia'
The National Weather Service adopted the Twitter hashtag "#Chiberia" for Chicago. Parts of the vast Siberian region, such as Tobolsk, had Fahrenheit temps in the low teens Monday, though other parts had temperatures of 50 below zero.
Chicago opened up 12 centers for residents to seek warmth, one of which was to stay open all night through Tuesday. Libraries and some other city facilities would also be open, said Evelyn Diaz of the city's Department of Family and Support Services. Quinn said 100 warming centers were open statewide.
The worst was still reaching down South on Monday night. In Atlanta, where Tuesday morning's low was projected to be in the single digits, Katie Fallon joked, "My shoes do not even match my outfit this morning! Had to go fuzzy socks and hiking boots for warmth." Atlanta's public schools were still closed for break Monday, and the city announced schools would remain closed Tuesday.
But by Wednesday, temperatures will start edging closer to normal, and by Thursday temperatures in most of the country will be back to normal -- or even a bit warmer, said CNN meteorologist Brandon Miller.
综合外国媒体1月7日报道，自当地时间6日起，受到极地漩涡的影响，美国本土大部分地区遭遇近20年来最低温。目前，极端严寒天气已导致全美15人死亡。
***芝加哥变身“芝伯利亚”
6日，芝加哥气温创下低温纪录，奥黑尔国际机场的气温降至零下27摄氏度。当天，美国国家气象局发布微博时为芝加哥取了一个新名字“芝伯利亚”（Chiberia），以此说明芝加哥的寒冷程度不亚于以严寒著称的俄罗斯西伯利亚地区。
那么，“芝伯利亚”究竟有多冷呢？确实很冷，就连动物园里的北极熊都被禁止在户外活动。
芝加哥林肯公园动物园发言人莎伦•杜瓦尔解释称，野生北极熊有厚厚的脂肪层，足以抵御零下46摄氏度的低温，但该动物园里的唯一一只北极熊“阿那纳”在人工饲养环境下长大，没有厚脂肪层防寒，所以它6日只能呆在温度为4.5摄氏度的室内。在匹兹堡市的国家鸟类公园，由于天气太过寒冷，秃鹰和非洲企鹅暂停展览。
此外，芝加哥市还开放了12个公共场所供市民取暖，其中一处6日晚彻夜开放。在芝加哥所处的伊利诺伊州，共开放了100个公共取暖中心。
***明尼苏达全州闭校
美国国家气象局表示，“极地漩涡”是造成全美大部分地区遭遇近20年最低气温的“罪魁祸首”。这场降温6日席卷美国中西部后，向东北部的华盛顿地区挺进。
在位于上中西部地区的明尼苏州，气温降至零下40摄氏度，体感温度最低为零下49摄氏度。明尼苏达州州长马克•戴顿下令，该州全部2000所公立学校6日停课，这是自1997年以来首次。7日，明尼苏达州多所学校将继续停课。
尽管气象部门发出警告称，气温降至零下40摄氏度时，皮肤暴露在寒风中几分钟就会冻伤，但是仍有民众不惧危险，走出户外体验难得的“极地乐园”。
“我喜欢寒冷的天气。我是疯狂热爱严寒的明尼苏达州人。”罗伯特•佩蒂特工歇时在雪地上散步，“其实只要穿得足够保暖，情况也不是太糟”。
***严寒天气已致15人死亡
据美国有线电视资讯网（CNN）报道，截至当地时间7日，极端严寒天气已导致全美15人死亡，多数为交通事故。其中，在纽约州西部，一名患有老年痴呆症的妇女外出时衣着单薄倒地身亡。在俄亥俄州克利夫兰市，一名病患因体温过低丧生。
极寒天气也严重影响到美国的交通秩序。在芝加哥市奥黑尔国际机场，5日晚有1200架次航班被取消，占到该机场当天航班总量的一半。在密苏里州东部城市圣路易斯和印第安纳州首府印第安纳波利斯，5日晚也有半数进出港航班被取消。6日，情况进一步恶化，多个机场的更多航班被取消或延迟。
在华盛顿地区，6日上午气温仍有4摄氏度，并伴有寒风。到7日凌晨，气温降至零度或零下，体感温度则骤降至零下21至零下26摄氏度。为此，当地政府公布了低温热线电话，为民众提供最新天气信息及咨询。
美国有线电视资讯网气象学家布兰登•米勒表示，6日至7日，美国南部地区将迎来此次降温气温最低谷，不过8日将开始升温，9日全美绝大部分地区的气温恢复正常，甚至略高于往年同期水平。