Deep Freeze Tightens Hold on the Great White North as America Sees Hottest Christmas on Record.
A prolonged deep freeze has enveloped an intense and prolonged cold spell, with temperatures hovering 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, its coldest December temperature in nearly five decades.
Enduring Chill in the Deep Minus Forties
In addition, the locales of Mayo and Dawson suffered through sixteen nights in a row below -40C, with Mayo experiencing a low of -50.4C earlier this week. The capital, Whitehorse, likewise saw 10 nights when the cold dipped under -30 Celsius.
This Arctic air mass pushed further southward through Christmas week. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.
December 26th was anticipated to usher in lows of at least -20C across many regions, from Edmonton in the west to Quebec in the east.
Forecast to Persist For Days to Come
This harsh winter weather is expected to continue through the start of January. 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 prolonged chill has been caused by 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.
Dramatic Difference to American Heat
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. Across wide regions, the atmosphere was more akin to late spring than late December.
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. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina similarly saw thermometers rise past the 25C mark.
Atmospheric Ridge Drives the Heat
Unseasonable heat is predicted to persist for the remainder of the week and beyond, 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. Such a configuration results in a widespread high-pressure system across much of the continent, effectively capping warm air at lower altitudes. Descending air compresses and adiabatically warms, allowing unusually warm temperatures to build.
