Extreme cold winter conditions are expected to trap the majority of the country in a bitter weather phenomenon known as a “polar vortex” over the coming days.
Environment Canada has issued weather warnings for most of Canada over a “high or moderate impact level” cold blast that is set to last throughout the weekend.
The daytime average across Toronto will be -12.5 C with the wind chill making it feel like -23 C, alongside wind gusts hitting up to 41 km/h, while temperatures will plunge to -40 to -50 across the Prairie provinces and -40 to -48 in northwestern Ontario.
Global News chief meteorologist Anthony Farnell said the extent of this system is what has meteorologists paying attention.
“Given how widespread it is, that’s what makes this rather remarkable, seeing how most of Canada is into this deep freeze,” he said. “We haven’t seen this in a couple of years.”
So, what exactly is a polar vortex?
According to the U.S. National Weather Service, the term polar vortex has only recently been popularized, but has always existed as a severe weather event.
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The term “vortex” refers to “the counterclockwise flow of air that helps keep the colder air near the Earth’s poles,” the agency says.
The National Weather Service also stated that throughout the winter season in the northern hemisphere, “the polar vortex will expand, sending cold air southward.”
The National Oceanographic and Atmospheric Administration in the U.S. states that an arctic polar vortex “is a band of strong westerly winds that form in the stratosphere between about 10 and 30 miles above the North Pole every winter,” which enclose “a large pool of extremely cold air.”
“Sometimes this low-pressure system, full of arctic air, can weaken and travel from its usual position,” the NOAA notes.
“As this system weakens, some of the cold, arctic air can break off and migrate south, bringing plenty of cold air with it. Areas as far south as Florida may experience arctic weather as a result.”
As a result, a polar vortex can be identified by weather forecasters “by looking at conditions tens of thousands of feet up in the atmosphere.”
Farnell said that polar vortexes are becoming “more common occurrences,” as the country has had its share of deep freezes in this past November and in January 2024 in Alberta.
“It seems we are getting more extremes, whether it’s warmth or in this case cold, and that is a byproduct of climate change,” he said. “You can sometimes see more extremes one way or the other because of that.”
For a considerable part of the country, this has been a tough winter already.
“From Saskatchewan, Manitoba, Ontario and Quebec, this has been a colder, snowier winter than normal,” Farnell said.
“For the Maritimes it has been a lot of back-and-forth — there’s been warmups, rain and then it gets cold. On the west coast, it’s been almost an easier winter; there hasn’t been a flake of snow in Vancouver yet.”
Environment Canada says the system will be a “multi-day event.”
A winter storm system is set to bring “potentially catastrophic” ice and snow amounts across large swathes of the United States from Friday through Sunday.
That system is set to clash with the polar vortex currently causing a deep freeze across much of Canada, with significant snowfall for regions including Ontario and Quebec starting Sunday afternoon and into the evening as it moves east.
“The arctic air that’s been around will be replaced with more Pacific air,” Farnell said. “That arctic air will retreat back to the north and reload.”
However, Farnell said that the harshness of this winter season will begin to thaw out after the first week of February, but not for long.
“Right now, it is unloading the arctic air, and it is going to moderate by early February and we may see another blast later in the month,” he said.
“We are not out of the woods yet.”
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