If you lived in central Canada last winter, you probably remember it looking something like this.
Manitoba, Ontario and Quebec all endured one of the worst winters on record as cold air from a polar vortex came south and just ... would ... not ... leave.
But what IS a polar vortex, exactly? And can we expect to see it again this winter?
A polar vortex is a system of strong, cold winds that swirl counterclockwise around the North Pole, CNN reported in January.
Those winds help to keep cold air in the Arctic. But sometimes the system can weaken and push frigid, Arctic air into regions further south, the network said.
Climate change is one reason why the polar vortex weakens, says Scientific American.
Arctic sea ice is currently melting at an increasing rate in the summer, warming the ocean. As this happens, much of that extra heat is then reflected back into the atmosphere in the winter, breaking up the vortex and allowing cold air to escape.
The magazine noted that a polar vortex is known to weaken in winters following summers in which a large amount of sea ice has melted away.
But can we expect a vortex to affect us again this year?
Yes, Environment Canada meteorologist David Phillips told Global News. But it's unlikely to unleash the same icy fury that it did last winter.
"Last year was a one-off," he told the network. "It was one of these things that was an outlier. They'll occur again. But the chances of them occurring again are very low."
So fret not. Winter is coming — but it likely won't be bad enough to bring the White Walkers.
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