Deep Freeze Tightens Hold on the Great White North as United States Experiences Most Unseasonably Mild Christmas in History.

Northern Canada has been gripped by a bitter and extended period of frigid weather, 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 in half a century.

Consecutive Nights in the Deep Minus Forties

Meanwhile, Mayo and Dawson endured sixteen nights in a row colder than minus 40 degrees, with Mayo plunging to -50.4C at the start of the week. Whitehorse also recorded ten separate 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.

Boxing Day was expected to bring minimum temperatures of at least minus 20C through a wide swath, from Edmonton in the west to Quebec in the east.

Forecast to Persist into the New Year

This harsh winter weather is expected to continue 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 record-high energy demand.

The lengthy cold snap originates from the Arctic vortex settling across the northern part of the continent this month, which funnels frigid northern air southward. In the coming week, forecasts indicate this cold air will pull back northward allowing more temperate air from the Pacific to sweep across the United States and penetrate southern Canadian regions.

Stark Contrast to American Heat

Conversely, sections of America recorded historically high temperatures for Christmas as temperatures soared about 15-30C above the seasonal average. In many areas, conditions felt more typical of April or May 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. Metropolitan areas such as Austin, Dallas, and Charlotte also logged readings above 25 degrees Celsius.

Heat-Dome Effect Drives the Heat

Warmer-than-normal conditions are forecast to last on December 26th and into the weekend, with unseasonable heat forecast to sweep through the American Southeast soon.

The unseasonable temperatures are powered by a strong upper-level ridge extending from the desert south-west towards the north and east, establishing a classic heat-dome pattern. 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, fostering the buildup of exceptional warmth.