The polar vortex hovering over Siberia has generated the coldest temperature on Earth so far this year, and according to meteorologists, it could be headed to Canada in early February.
“We’re showing a large area from all of British Columbia, all of the Prairies, the Northwest Territories, the Yukon, and right through to Northwestern Ontario as being colder than normal for the month of February,” David Phillips, Environment Canada’s chief meteorologist, told CTVNews.ca in a telephone interview Tuesday. “I think that is a direct result of the diving down southward of the polar vortex.”
A weather station in Tongulakh, Siberia recorded a temperature of -62.4 C on Jan. 14 as a pocket of frigid arctic air hovered over northern Russia. For reference, that temperature is only 0.3 C from the average temperature on Mars; cold enough to freeze exposed skin in seconds. It’s the coldest temperature Russia has recorded in two decades.
In ideal conditions, Phillips explained, the polar vortices stay over the North and South Poles, held in place by their own powerful rotations and strong polar jet streams that circulate counterclockwise – or west – around the Earth’s upper latitudes to the north and south.
In the Northern Hemisphere, the polar jet separates the polar vortex from warmer, temperate air to the south. When the vortex holds its shape and stays concentrated over the pole, it is considered a strong vortex. However, sometimes warmer air from the south creeps north over the vortex, and dips down into the vortex from higher in the atmosphere, displacing the cold air.
When this happens, the entire vortex can shift off of the pole, or parts of it can leak or break off and drift into the lower latitudes – into Europe, North America and Asia.
Although the polar vortex is concentrated in the stratosphere, Doug Gillham, meteorologist at The Weather Network, said it tends to bring cold air down to the troposphere wherever it goes.
“It’s well up in the atmosphere, several kilometres up, but it’s associated generally with the coldest air in the hemisphere,” he told CTVNews.ca in a telephone interview on Tuesday. “So down where we live, when the polar vortex gets displaced from the pole, it will often bring cold air with it.”
WHEN COULD THE POLAR VORTEX HIT CANADA?
Right now, Gillham said, the entire vortex has shifted so that the bulk of it is hovering over northern Russia. However, it will likely begin to shift again around the end of January.
“What we have right now is the biggest piece is over Siberia, and there’s been some record-breaking cold air associated with that,” he said.
When cold weather does come to Canada in February, Gillham said it will be because shifts in the jet stream cause the polar vortex to dissipate and re-form over western Canada, replacing the warm air that’s settled over the country in recent weeks.
“We’ve had a powerful jet stream over the North Pacific and it’s just been flooding pretty much all of North America with mild air from the Pacific Ocean,” he said.
“The jet stream is going to change in a way that will stop flooding the continent with mild Pacific air, and we’ll start to see the Arctic air drain south. And so our winter vacation is coming to an end.”
According to The Weather Network, while Western Canada and the Prairies can expect a blast of cold weather soon, major cities across Eastern Canada are on track to see the warmest winter on record. The weather agency reports Halifax has experienced an average temperature of 1.5 C so far this winter.
For Southern Ontario and Quebec, Gillham said cold air from the northwest and warm air from the southeast could clash to create some volatile weather when the polar vortex shifts again.
“Being the battle zone means we’ll get a more active storm track, which means a lot of messy weather systems, the potential for heavy snow, but also the potential for ice and rain.”