National Weather Service: 'One of the coldest arctic air mass intrusions in recent memory is surging south into the Upper Midwest before spreading across much of the eastern two-thirds of the country'
Temperatures in almost a dozen states from the Dakotas to Ohio were forecast to be the coldest in a generationChicago, America's third largest city, was expected to be colder than parts of AntarcticaAmericans were asked to stay home if possible today, when temperatures are expected to be at their coldest.Scientists say climate change is causing more extreme weather, and one theory for polar vortex chills is that arctic air currents usually trapped around the North Pole are weakened and dislodged by a warming climatePeople gather at Neighborhood Service Organization in Detroit - warming centres have been opened in many citiesThe National Weather Service forecast temperatures between -23 to -40C across the MidwestJen and Aaron Brackman wrap up well as they cross the Stone Arch Bridge in MinneapolisIn Canada, the icy temperatures prompted a rare 'hazardous' cold warning from the governmentNWS: 'Expect frigid temperatures, bitterly cold and life-threatening wind chills'According to meteorologists, temperatures in Chicago area could drop to -24F (-31C)Chloe Adams went for a ski run with her dog Roscoe as wind chills reached -34C in MinneapolisAs much as 60cm of snow was forecast in Wisconsin and 15cm in Illinois
