Deep Freeze Grips the Great White North as US Records Most Unseasonably Mild Christmas in History.
A prolonged deep freeze has enveloped a severe and lengthy Arctic outbreak, with readings persisting between -20C and -40C for weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, its coldest December temperature since 1975.
Consecutive Nights 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 ten separate nights when the cold dipped under -30 Celsius.
The bitter chill extended its reach south over the festive period. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
Boxing Day was expected to bring minimum temperatures of at least minus 20C in numerous areas, from Edmonton in the west to Quebec in the east.
Forecast to Persist Through Early January
The frigid conditions are predicted to linger through the start of January. Authorities have cautioned about potential power failures in the Yukon over the next several days, as the system endures record-high pressure from historically high electricity consumption.
The lengthy cold snap originates from a stationary polar vortex over Canada for much of December, 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 the US and into parts of southern Canada.
Pronounced Disparity to American Heat
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. For numerous locations, the weather resembled a spring day in April or May rather than the end of December.
A number of states broke historical records for December 25th warmth. The capital of Oklahoma soared to 25C on Christmas Day, exceeding the old record of 22C from 1982. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina similarly saw thermometers rise past the 25C mark.
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 across the southeastern US in the coming days.
This heat is being driven by a strong upper-level ridge reaching from the arid southwest across the continent, establishing a classic heat-dome pattern. This setup creates an extensive zone of high atmospheric pressure over a large portion of North America, effectively capping warm air at lower altitudes. As air sinks through the atmosphere, it compresses and heats further, allowing unusually warm temperatures to build.