A prolonged deep freeze has enveloped an intense and prolonged cold spell, with thermometers lingering from 20 to 40 degrees below zero for weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, marking its chilliest December reading in nearly five decades.
Enduring Chill in the Deep Minus Forties
Meanwhile, Mayo and Dawson endured 16 consecutive nights colder than minus 40 degrees, with Mayo plunging to -50.4C earlier this week. Whitehorse similarly reported 10 nights when temperatures dropped below -30C.
The deep freeze spread farther south through Christmas week. Christmas night saw Edmonton's temperatures plummet below minus 28C.
Boxing Day was expected to bring minimum temperatures of at least minus 20C in numerous areas, encompassing cities from Edmonton to Quebec.
Forecast to Persist Through Early January
The frigid conditions are predicted to linger into the new year. Officials have warned that the Yukon could face electricity outages soon, as its energy infrastructure faces unprecedented demand from peak power usage levels.
The prolonged chill has been caused by the polar vortex remaining anchored across the northern part of the continent this month, 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 US and into parts of southern Canada.
Pronounced Disparity with US Warmth
Meanwhile, in a dramatic contrast, areas of the United States saw the hottest December 25th in their history as readings skyrocketed 15 to 30 degrees Celsius above normal. In many areas, conditions felt more typical of April or May rather than the end of December.
Several states set Christmas Day temperature records. Oklahoma City, Oklahoma, reached 25 degrees Celsius on Christmas, surpassing the previous peak of 22C set in 1982. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina also logged readings above 25 degrees Celsius.
Atmospheric Ridge Sustains High Temperatures
Warmer-than-normal conditions are forecast to last through Boxing Day and the days ahead, with atypical high temperatures expected to spread through the American Southeast soon.
The unseasonable temperatures are powered by a strong upper-level ridge stretching from the southwestern deserts northward and eastward, establishing a classic heat-dome pattern. Such a configuration results in a widespread high-pressure system over a large portion of North America, trapping warm air near the surface. Descending air compresses and adiabatically warms, fostering the buildup of exceptional warmth.
