🔗 Share this article

A prolonged deep freeze has enveloped a bitter and extended period of frigid weather, with thermometers lingering in the minus 20 to minus 40 Celsius range for weeks. On Tuesday, Braeburn in the Yukon recorded -55.7C, representing its most frigid December day in half a century.

Enduring Chill of Extreme Cold

Meanwhile, Mayo and Dawson endured sixteen nights in a row colder than minus 40 degrees, with Mayo experiencing a low of -50.4C at the start of the week. The capital, Whitehorse, likewise saw 10 nights when temperatures dropped below -30C.

This Arctic air mass pushed further southward over the festive period. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.

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

Expected to Continue Through Early January

This harsh winter weather is expected to continue through the start of January. Officials have warned that the Yukon could face electricity outages soon, as the territory’s power grid comes under strain from historically high electricity consumption.

The lengthy cold snap originates from the Arctic vortex settling above Canadian territory through December, enabling a surge of icy Arctic winds to descend. In the coming week, forecasts indicate this cold air will pull back northward gradually, enabling milder Pacific air to move across the US and into parts of southern Canada.

Pronounced Disparity 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. Across wide regions, the atmosphere was more akin to late spring than late December.

A number of states broke historical records for December 25th warmth. 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 also logged readings above 25 degrees Celsius.

Heat-Dome Effect Drives the Heat

Above-average warmth is expected to continue for the remainder of the week and beyond, with atypical high temperatures expected to spread through the American Southeast soon.

This heat is being driven by a powerful high-altitude ridge extending from the desert south-west towards the north and east, creating a heat-dome effect. This setup creates an extensive zone of high atmospheric pressure across much of the continent, effectively capping warm air at lower altitudes. Sinking atmospheric air undergoes compression and additional heating, enabling abnormally high temperatures to develop.