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A prolonged deep freeze has enveloped a bitter and extended period of frigid weather, with temperatures hovering from 20 to 40 degrees below zero for multiple weeks. On Tuesday, Braeburn in the Yukon recorded -55.7C, its coldest December temperature in half a century.

Prolonged Freeze in the Deep Minus Forties

Similarly, the communities of Mayo and Dawson experienced sixteen nights in a row colder than minus 40 degrees, with Mayo experiencing a low of -50.4C earlier this week. Whitehorse similarly reported a series of ten nights when temperatures dropped below -30C.

The deep freeze spread farther south through Christmas week. Christmas night saw Edmonton's temperatures plummet below minus 28C.

The day after Christmas was forecast to deliver lows of at least -20C in numerous areas, including Edmonton, Montreal, Ottawa and Quebec.

Forecast to Persist For Days to Come

The frigid conditions are predicted to linger for the foreseeable future. There are warnings of possible electrical grid strain in Yukon territory soon, as its energy infrastructure faces unprecedented demand from peak power usage levels.

This extended freeze is the result of the Arctic vortex settling above Canadian territory through December, which funnels frigid northern air southward. In the coming week, forecasts indicate this cold air will pull back northward slowly, permitting warmer Pacific winds to flow over the US and into parts of southern Canada.

Dramatic Difference Compared to Stateside Temperatures

Conversely, sections of America recorded their warmest Christmas Day on record as temperatures soared about 15-30C above the seasonal average. Across wide regions, the atmosphere was more akin to late spring rather than the end of December.

Multiple states established new Christmas temperature highs. The capital of Oklahoma soared to 25C on Christmas Day, topping the prior high mark of 22 degrees established over forty years ago. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina also logged readings above 25 degrees Celsius.

Heat-Dome Effect Drives the Heat

Above-average warmth is expected to continue for the remainder of the week and beyond, with atypical high temperatures expected to spread across the southeastern US in the coming days.

This heat is being driven by a powerful high-altitude ridge extending from the desert south-west towards the north and east, establishing a classic heat-dome pattern. This pattern establishes a broad area of high pressure across much of the continent, effectively capping warm air at lower altitudes. As air sinks through the atmosphere, it compresses and heats further, fostering the buildup of exceptional warmth.