Deep Freeze Envelops Canada as America Sees Most Unseasonably Mild Christmas in History.
A prolonged deep freeze has enveloped an intense and prolonged cold spell, with readings persisting between -20C and -40C for weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, marking its chilliest December reading in nearly five decades.
Consecutive Nights of Extreme Cold
Similarly, the communities of Mayo and Dawson experienced over two straight weeks of nights below -40C, with Mayo plunging to -50.4C on Monday. The capital, Whitehorse, likewise saw ten separate nights when readings fell to minus 30 degrees or lower.
The deep freeze spread farther south during the holiday season. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
December 26th was anticipated to usher in readings no higher than -20 Celsius across many regions, encompassing cities from Edmonton to Quebec.
Expected to Continue For Days to Come
The frigid conditions are predicted to linger for the foreseeable future. Authorities have cautioned about potential power failures in the Yukon in the coming days, as its energy infrastructure faces unprecedented demand from historically high electricity consumption.
The lengthy cold snap originates from the Arctic vortex settling across the northern part of the continent this month, which funnels frigid northern air southward. Next week, the cold air mass is expected to retreat north gradually, enabling milder Pacific air to move across America and reach into portions of southern Canada.
Dramatic Difference with US Warmth
Meanwhile, in a dramatic contrast, areas of the United States saw the hottest December 25th in their history as temperatures soared about 15-30C above the seasonal average. For numerous locations, the weather resembled a spring day in April or May than late December.
Several states set Christmas Day temperature records. In Oklahoma, Oklahoma City hit 25C on Tuesday, topping the prior high mark of 22 degrees established over forty years ago. Urban centers like Austin, Dallas, and Charlotte, North Carolina similarly saw thermometers rise past the 25C mark.
Heat-Dome Effect Drives the Heat
Warmer-than-normal conditions are forecast to last for the remainder of the week and beyond, with unseasonable heat forecast to sweep into the south-eastern states later in the week.
The warmth has been fuelled by a powerful high-altitude ridge extending from the desert south-west towards the north and east, which generates a heat-dome phenomenon. Such a configuration results in a widespread high-pressure system over a large portion of North America, trapping warm air near the surface. Sinking atmospheric air undergoes compression and additional heating, allowing unusually warm temperatures to build.
