Prolonged Chill Tightens Hold on the Great White North as US Records Hottest Christmas Ever.

Northern Canada has been gripped by an intense and prolonged cold spell, with readings persisting from 20 to 40 degrees below zero for an extended duration. On Tuesday, Braeburn in the Yukon recorded -55.7C, representing its most frigid December day in nearly five decades.

Consecutive Nights in the Deep Minus Forties

Meanwhile, Mayo and Dawson endured sixteen nights in a row below -40C, with Mayo experiencing a low of -50.4C earlier this week. The capital, Whitehorse, likewise saw ten separate nights when readings fell to minus 30 degrees or lower.

The deep freeze spread farther south during the holiday season. On Christmas Day, overnight temperatures in Edmonton fell below -28C.

The day after Christmas was forecast to deliver minimum temperatures of at least minus 20C across many regions, including Edmonton, Montreal, Ottawa and Quebec.

Expected to Continue For Days to Come

The severe cold is forecast to persist through the start of January. There are warnings of possible electrical grid strain in Yukon territory in the coming days, as its energy infrastructure faces unprecedented demand from record-high energy demand.

The prolonged chill has been caused by a stationary polar vortex across the northern part of the continent this month, which funnels frigid northern air southward. Next week, the cold air mass is expected to retreat north allowing more temperate air from the Pacific to sweep across the United States and penetrate southern Canadian regions.

Dramatic Difference to American Heat

In stark contrast, parts of the US experienced 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 instead of the heart of winter.

Several states set Christmas Day temperature records. 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 similarly saw thermometers rise past the 25C mark.

Heat-Dome Effect Sustains High Temperatures

Warmer-than-normal conditions are forecast to last on December 26th and into the weekend, with abnormal warmth projected to move through the American Southeast soon.

This heat is being driven by a powerful high-altitude ridge stretching from the southwestern deserts northward and eastward, which generates a heat-dome phenomenon. This setup creates an extensive zone of high atmospheric pressure blanketing a significant part of the landmass, effectively capping warm air at lower altitudes. Sinking atmospheric air undergoes compression and additional heating, allowing unusually warm temperatures to build.