Polar vortex of bitter cold in U.S. kills at least 21
Great Lakes region hit the hardest by winter chill08 January, 19:41
The bitter chill has swept across the US, from the northeastern areas to the Gulf of Mexico. Many flights were cancelled or delayed, with the worst-hit area around the Great Lakes, from Chicago to Detroit.
By Wednesday evening, the temperature was rising slightly and heavy snowfall had become a greater concern in certain areas.