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An intense cold spell has seized a severe and lengthy Arctic outbreak, with thermometers lingering between -20C and -40C for an extended duration. On Tuesday, Braeburn in the Yukon recorded -55.7C, its coldest December temperature since 1975.

Consecutive Nights in the Deep Minus Forties

In addition, the locales of Mayo and Dawson suffered through 16 consecutive nights colder than minus 40 degrees, with Mayo experiencing a low of -50.4C on Monday. The capital, Whitehorse, likewise saw a series of ten nights when temperatures dropped below -30C.

This Arctic air mass pushed further southward through Christmas week. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.

Boxing Day was expected to bring readings no higher than -20 Celsius in numerous areas, from Edmonton in the west to Quebec in the east.

Expected to Continue For Days to Come

The frigid conditions are predicted to linger for the foreseeable future. Officials have warned that the Yukon could face electricity outages in the coming days, as its energy infrastructure faces unprecedented demand from historically high electricity consumption.

The prolonged chill has been caused by the polar vortex remaining anchored across the northern part of the continent this month, which funnels frigid northern air southward. In the coming week, forecasts indicate this cold air will pull back northward gradually, enabling milder Pacific air to move across the US and into parts of southern Canada.

Stark Contrast Compared to Stateside Temperatures

Meanwhile, in a dramatic contrast, areas of the United States saw historically high temperatures for Christmas as temperatures soared about 15-30C above the seasonal average. For numerous locations, the weather resembled a spring day in April or May rather than the end of December.

Multiple states established new Christmas temperature highs. In Oklahoma, Oklahoma City hit 25C on Tuesday, surpassing the previous peak of 22C set in 1982. Metropolitan areas such as Austin, Dallas, and Charlotte were also among those that recorded temperatures above 25C.

Heat-Dome Effect Fuels Warmth

Warmer-than-normal conditions are forecast to last on December 26th and into the weekend, with abnormal warmth projected to move across the southeastern US in the coming days.

This heat is being driven by a robust atmospheric ridge reaching from the arid southwest across the continent, establishing a classic heat-dome pattern. This pattern establishes a broad area of high pressure across much of the continent, which holds warm air close to the ground. Sinking atmospheric air undergoes compression and additional heating, fostering the buildup of exceptional warmth.