Siberian air is descending on Canada. Here's what to know about the 'polar vortex'
The intense cold snap about to settle over most of Canada and the U.S. has been dubbed a “polar vortex’, but Environment ...
Polar vortex maps show where arctic blast is set to freeze the U.S. as far as the Deep South
A polar vortex dipping down from Siberia will bring a cold front with frigid temperatures to nearly 300 million Americans.