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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 weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, its coldest December temperature in half a century.

Consecutive Nights Below -40C

Meanwhile, Mayo and Dawson endured 16 consecutive nights below -40C, with the temperature in Mayo bottoming out at -50.4 degrees Celsius on Monday. Whitehorse also recorded a series of ten nights when temperatures dropped below -30C.

The deep freeze spread farther south through Christmas week. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.

The day after Christmas was forecast to deliver minimum temperatures of at least minus 20C through a wide swath, 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. Officials have warned that the Yukon could face electricity outages over the next several days, as the territory’s power grid comes under strain from peak power usage levels.

This extended freeze is the result of the Arctic vortex settling over Canada for much of December, enabling a surge of icy Arctic winds to descend. The frigid dome is projected to gradually withdraw north slowly, permitting warmer Pacific winds to flow over America and reach into portions of southern Canada.

Pronounced Disparity 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. In many areas, conditions felt more typical of April or May than late December.

Several states set Christmas Day temperature records. Oklahoma City, Oklahoma, reached 25 degrees Celsius on Christmas, topping the prior high mark of 22 degrees established over forty years ago. Urban centers like Austin, Dallas, and Charlotte, North Carolina were also among those that recorded temperatures above 25C.

Atmospheric Ridge Drives the Heat

Warmer-than-normal conditions are forecast to last on December 26th and into the weekend, with atypical high temperatures expected to spread through the American Southeast soon.

This heat is being driven by a strong upper-level ridge stretching from the southwestern deserts northward and eastward, creating a heat-dome effect. Such a configuration results in a widespread high-pressure system across much of the continent, which holds warm air close to the ground. As air sinks through the atmosphere, it compresses and heats further, enabling abnormally high temperatures to develop.