Deep Freeze Grips the Great White North as US Records Most Unseasonably Mild Christmas on Record.
A prolonged deep freeze has enveloped an intense and prolonged cold spell, with thermometers lingering in the minus 20 to minus 40 Celsius range for weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, representing its most frigid December day since 1975.
Prolonged Freeze Below -40C
Similarly, the communities of Mayo and Dawson experienced sixteen nights in a row colder than minus 40 degrees, with Mayo experiencing a low of -50.4C at the start of the week. Whitehorse also recorded 10 nights when readings fell to minus 30 degrees or lower.
The bitter chill extended its reach south over the festive period. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
The day after Christmas was forecast to deliver readings no higher than -20 Celsius through a wide swath, encompassing cities from Edmonton to Quebec.
Expected to Continue For Days to Come
The frigid conditions are predicted to linger into the new year. Officials have warned that the Yukon could face electricity outages in the coming days, as its energy infrastructure faces unprecedented demand from peak power usage levels.
The lengthy cold snap originates from a stationary polar vortex above Canadian territory through 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.
Dramatic Difference with US Warmth
In stark contrast, parts of the US experienced the hottest December 25th in their history as temperatures soared about 15-30C above the seasonal average. Across wide regions, the atmosphere was more akin to late spring rather than the end of December.
A number of states broke historical records for December 25th warmth. 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 similarly saw thermometers rise past the 25C mark.
High-Pressure System Drives the Heat
Warmer-than-normal conditions are forecast to last on December 26th and into the weekend, with unseasonable heat forecast to sweep across the southeastern US in the coming days.
The warmth has been fuelled by a robust atmospheric ridge stretching from the southwestern deserts northward and eastward, which generates a heat-dome phenomenon. This pattern establishes a broad area of high pressure blanketing a significant part of the landmass, effectively capping warm air at lower altitudes. Descending air compresses and adiabatically warms, fostering the buildup of exceptional warmth.
