Arctic Blast Tightens Hold on the Great White North as US Records Warmest Christmas Ever.

Northern Canada has been gripped by an intense and prolonged cold spell, with temperatures hovering from 20 to 40 degrees below zero for weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, representing its most frigid December day since 1975.

Enduring Chill in the Deep Minus Forties

In addition, the locales of Mayo and Dawson suffered through sixteen nights in a row colder than minus 40 degrees, with Mayo experiencing a low of -50.4C earlier this week. Whitehorse similarly reported 10 nights when the cold dipped under -30 Celsius.

The deep freeze spread farther south during the holiday season. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.

December 26th was anticipated to usher in minimum temperatures of at least minus 20C through a wide swath, including Edmonton, Montreal, Ottawa and Quebec.

Expected to Continue into the New Year

The severe cold is forecast to persist into the new year. Authorities have cautioned about potential power failures in the Yukon over the next several days, as the territory’s power grid comes under strain from historically high electricity consumption.

The prolonged chill has been caused by the polar vortex remaining anchored 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 United States and penetrate southern Canadian regions.

Dramatic Difference with US Warmth

Conversely, sections of America recorded 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 than late December.

A number of states broke historical records for December 25th warmth. In Oklahoma, Oklahoma City hit 25C on Tuesday, 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.

Heat-Dome Effect Fuels Warmth

Unseasonable heat is predicted to persist for the remainder of the week and beyond, with atypical high temperatures expected to spread through the American Southeast soon.

The warmth has been fuelled by a powerful high-altitude ridge stretching from the southwestern deserts northward and eastward, creating a heat-dome effect. Such a configuration results in a widespread high-pressure system across much of the continent, trapping warm air near the surface. Sinking atmospheric air undergoes compression and additional heating, fostering the buildup of exceptional warmth.