It’s official: the freezing polar vortex is back in North America!

Prepare yourselves dear inhabitants. As of Thursday morning, Canada and several states in the northern United States are expected to experience a dramatic drop in temperatures of up to -35°C.

After an abnormally mild and clement autumn, the polar vortex, which had so far been discreet, will enter through the front door this week. A wave of cold polar air is preparing to sweep across Canada and the northern United States this Thursday. Called « polar vortex », this extreme climatic phenomenon will lead in the coming days to spectacular drops in temperatures which should reach – 35° in places, as illustrated by this animation posted online by NASA.

The polar vortex acts both in winter and in summer, but its effects are still more felt in winter since the atmosphere is less heated by the sun’s rays. After a first surge of cold air as an appetizer recorded in early December, residents of Minnesota, Wisconsin, part of Dakota and the city of Chicago should have a taste of the dish as early as Thursday morning. resistance with temperatures approaching -30°C, whereas in Canada and New England, they may decrease to -35°C.

The polar vortex is a kind of vortex that spins counter-clockwise and traps cold air over the Arctic. It is usually held in place by the jet stream, a band of winds between 15,000 and 20,000 feet above the Earth that separates cold air from warm air, but it also happens to move southward which corresponds to eastern Canada and the United States. This is the current phenomenon.

Note that the last major polar vortex was observed in January 2014 in the United States with an at least equivalent cold snap. Despite these record lows, let’s not forget that 2016 is still on track to be the hottest year on record globally, with temperatures 20 degrees above normal in the Arctic.


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