Deep Freeze Tightens Hold on the Great White North as America Sees Most Unseasonably Mild Christmas in History.
A prolonged deep freeze has enveloped a bitter and extended period of frigid weather, with thermometers lingering between -20C and -40C for multiple weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, representing its most frigid December day since 1975.
Enduring Chill in the Deep Minus Forties
Similarly, the communities of Mayo and Dawson experienced over two straight weeks of nights dipping under the minus 40 Celsius threshold, with the temperature in Mayo bottoming out at -50.4 degrees Celsius earlier this week. Whitehorse also recorded 10 nights when readings fell to minus 30 degrees or lower.
This Arctic air mass pushed further southward over the festive period. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
Boxing Day was expected to bring readings no higher than -20 Celsius in numerous areas, encompassing cities from Edmonton to Quebec.
Likely to Linger For Days to Come
This harsh winter weather is expected to continue for the foreseeable future. There are warnings of possible electrical grid strain in Yukon territory 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 above Canadian territory through December, allowing bitter Arctic air to spill south. Next week, the cold air mass is expected to retreat north allowing more temperate air from the Pacific to sweep across the United States and penetrate southern Canadian regions.
Stark Contrast Compared to Stateside Temperatures
Meanwhile, in a dramatic contrast, areas of the United States saw historically high temperatures for Christmas as readings skyrocketed 15 to 30 degrees Celsius above normal. In many areas, conditions felt more typical of April or May instead of the heart of winter.
Multiple states established new Christmas temperature highs. 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
Above-average warmth is expected to continue for the remainder of the week and beyond, with abnormal warmth projected to move into the south-eastern states later in the week.
The unseasonable temperatures are powered by a powerful high-altitude ridge stretching from the southwestern deserts northward and eastward, which generates a heat-dome phenomenon. Such a configuration results in a widespread high-pressure system blanketing a significant part of the landmass, which holds warm air close to the ground. Descending air compresses and adiabatically warms, fostering the buildup of exceptional warmth.
