Deep Freeze Grips Canada as US Records Warmest Christmas in History.

An intense cold spell has seized a severe and lengthy Arctic outbreak, with readings persisting from 20 to 40 degrees below zero for multiple weeks. On Tuesday, Braeburn in the Yukon recorded -55.7C, marking its chilliest December reading in half a century.

Consecutive Nights Below -40C

Meanwhile, Mayo and Dawson endured 16 consecutive nights colder than minus 40 degrees, with the temperature in Mayo bottoming out at -50.4 degrees Celsius earlier this week. The capital, Whitehorse, likewise saw a series of ten nights when the cold dipped under -30 Celsius.

This Arctic air mass pushed further southward over the festive period. Christmas night saw Edmonton's temperatures plummet below minus 28C.

The day after Christmas was forecast to deliver lows of at least -20C across many regions, encompassing cities from Edmonton to 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 soon, as its energy infrastructure faces unprecedented demand from peak power usage levels.

The lengthy cold snap originates from the polar vortex remaining anchored over Canada for much of December, 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 US and into parts of southern Canada.

Stark Contrast to American Heat

Meanwhile, in a dramatic contrast, areas of the United States saw historically high temperatures for Christmas as the mercury climbed roughly 15 to 30 degrees above typical averages. Across wide regions, the atmosphere was more akin to late spring instead of the heart of winter.

Several states set Christmas Day temperature records. The capital of Oklahoma soared to 25C on Christmas Day, 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.

High-Pressure System Fuels Warmth

Above-average warmth is expected to continue for the remainder of the week and beyond, with abnormal warmth projected to move into the south-eastern states later in the week.

The warmth has been fuelled by a powerful high-altitude ridge extending from the desert south-west towards the north and east, which generates a heat-dome phenomenon. This pattern establishes a broad area of high 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.