The coldest temperatures of the winter season have settled across British Columbia and Alberta.
Highs struggled to rise above -25°C in Alberta on Monday, with Grande Prairie leading the chill at a bone-chilling -28.7°C. Overnight lows plummeted near -44°C in Teepee Creek, Alta. At those temperatures, boiling water in the snow instantly turns into ice crystals before hitting the ground.
DON'T MISS: Heavy snowfall of up to 20 cm expected as cold weather dominates the Prairies
While these temperatures are more than 20°C below seasonal norms, they fall short of record-breaking lows. Still, they mark a significant departure from a typical February day.
The main culprit behind this frigid spell is the stratospheric polar vortex, which has shifted to this side of the pole. Originating from the high Arctic, this frigid air spiralled southward, gripping Western Canada in its icy hold.
At the surface, a sprawling Arctic high stretches from the Yukon to Saskatchewan, reinforcing the deep freeze. A healthy snowpack across the South Coast of B.C. acts like a natural coolant, allowing temperatures to drop even further, especially under clear night skies.
Typically, the jet stream moderates temperatures, with Pacific onshore flow helping to limit Arctic air intrusion. This week, however, upper-level winds are unusually calm, and the polar jet stream has been pushed as far south as California, leaving Western Canada exposed to extreme cold.
Strong ridging over Alaska often signals incoming cold air outbreaks, and this week is no exception. The ridge nearly touches the North Pole, while a potent lobe of the polar vortex--with roots in Siberia--is set to descend upon Western Canada.
By mid-month, another wave of frigid Arctic air could arrive. However, signs point to a more active Pacific jet stream, potentially leading to turbulent atmospheric clashes between Pacific moisture and lingering Arctic air.
Looking back at historical February cold snaps, the most recent occurrence in 2021 doesn't perfectly mirror this event. Instead, February 2019 stands out as an extreme example of just how bitter February can get.
Don't worry, this February won't be that cold as some locations averaged nearly 20°C below seasonal for the entire month.
February 2018 offers a partial match, with its cold anomaly stretching from B.C. to southwestern Manitoba.
February 2017 had similar temperatures in B.C., but the cold failed to spread east of the Rockies, unlike this year.
Here are some of the coldest February mean temperatures in recent memory and records for key Western Canadian cities:
The transition out of this deep freeze will likely be gradual rather than sudden. Even into mid-February, areas near the Canada-U.S. border will continue to experience below-seasonal temperatures.
Until the thaw arrives, Western Canada remains at the mercy of winter's unrelenting grip. Bundle up--the deep freeze isn't over, yet.