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An intense cold spell has seized a severe and lengthy Arctic outbreak, with readings persisting in the minus 20 to minus 40 Celsius range for an extended duration. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, marking its chilliest December reading in nearly five decades.

Prolonged Freeze in the Deep Minus Forties

Similarly, the communities of Mayo and Dawson experienced 16 consecutive nights below -40C, with the temperature in Mayo bottoming out at -50.4 degrees Celsius on Monday. Whitehorse also recorded ten separate nights when the cold dipped under -30 Celsius.

The deep freeze spread farther south during the holiday season. Christmas night saw Edmonton's temperatures plummet below minus 28C.

The day after Christmas was forecast to deliver readings no higher than -20 Celsius in numerous areas, including Edmonton, Montreal, Ottawa and Quebec.

Likely to Linger For Days to Come

This harsh winter weather is expected to continue for the foreseeable future. Authorities have cautioned about potential power failures in the Yukon in the coming days, as the system endures record-high pressure from historically high electricity consumption.

The lengthy cold snap originates from the polar vortex remaining anchored above Canadian territory through December, enabling a surge of icy Arctic winds to descend. Next week, the cold air mass is expected to retreat north gradually, enabling milder Pacific air to move across the US and into parts of southern Canada.

Pronounced Disparity with US Warmth

Meanwhile, in a dramatic contrast, areas of the United States saw their warmest Christmas Day on record as readings skyrocketed 15 to 30 degrees Celsius above normal. Across wide regions, the atmosphere was more akin to late spring instead of the heart of winter.

Several states set Christmas Day temperature records. Oklahoma City, Oklahoma, reached 25 degrees Celsius on Christmas, exceeding the old record of 22C from 1982. Urban centers like Austin, Dallas, and Charlotte, North Carolina similarly saw thermometers rise past the 25C mark.

High-Pressure System Sustains High Temperatures

Warmer-than-normal conditions are forecast to last for the remainder of the week and beyond, with abnormal warmth projected to move through the American Southeast soon.

This heat is being driven by a robust atmospheric ridge extending from the desert south-west towards the north and east, which generates a heat-dome phenomenon. This setup creates an extensive zone of high atmospheric pressure blanketing a significant part of the landmass, trapping warm air near the surface. Sinking atmospheric air undergoes compression and additional heating, allowing unusually warm temperatures to build.