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Northern Canada has been gripped by a bitter and extended period of frigid weather, with thermometers lingering between -20C and -40C for weeks. On Tuesday, Braeburn in the Yukon recorded -55.7C, marking its chilliest December reading in nearly five decades.

Consecutive Nights Below -40C

Similarly, the communities of Mayo and Dawson experienced sixteen nights in a row below -40C, with Mayo experiencing a low of -50.4C on Monday. The capital, Whitehorse, likewise saw 10 nights when temperatures dropped below -30C.

This Arctic air mass pushed further southward during the holiday season. Christmas night saw Edmonton's temperatures plummet below minus 28C.

The day after Christmas was forecast to deliver minimum temperatures of at least minus 20C through a wide swath, encompassing cities from Edmonton to Quebec.

Likely to Linger Through Early January

The severe cold is forecast to persist through the start of January. Officials have warned that the Yukon could face electricity outages in the coming days, as the system endures record-high pressure from record-high energy demand.

The prolonged chill has been caused by the polar vortex remaining anchored across the northern part of the continent this month, allowing bitter Arctic air to spill south. Next week, the cold air mass is expected to retreat north slowly, permitting warmer Pacific winds to flow over the United States and penetrate southern Canadian regions.

Dramatic Difference with US Warmth

Conversely, sections of America recorded their warmest Christmas Day on record as readings skyrocketed 15 to 30 degrees Celsius above normal. For numerous locations, the weather resembled a spring day in April or May instead of the heart of winter.

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. Metropolitan areas such as Austin, Dallas, and Charlotte were also among those that recorded temperatures above 25C.

Heat-Dome Effect Sustains High Temperatures

Warmer-than-normal conditions are forecast to last on December 26th and into the weekend, with atypical high temperatures expected to spread across the southeastern US in the coming days.

The warmth has been fuelled by a powerful high-altitude ridge reaching from the arid southwest across the continent, which generates a heat-dome phenomenon. This setup creates an extensive zone of high atmospheric pressure over a large portion of North America, trapping warm air near the surface. Sinking atmospheric air undergoes compression and additional heating, fostering the buildup of exceptional warmth.