Deep Freeze Tightens Hold on Canada as America Sees Most Unseasonably Mild Christmas in History.

Northern Canada has been gripped by an intense and prolonged cold spell, with temperatures hovering from 20 to 40 degrees below zero for weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, marking its chilliest December reading since 1975.

Prolonged Freeze of Extreme Cold

Similarly, the communities of Mayo and Dawson experienced sixteen nights in a row colder than minus 40 degrees, with the temperature in Mayo bottoming out at -50.4 degrees Celsius on Monday. The capital, Whitehorse, likewise saw ten separate nights when readings fell to minus 30 degrees or lower.

The deep freeze spread farther south over the festive period. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.

December 26th was anticipated to usher in readings no higher than -20 Celsius in numerous areas, from Edmonton in the west to Quebec in the east.

Forecast to Persist For Days to Come

The frigid conditions are predicted to linger through the start of January. Officials have warned that the Yukon could face electricity outages soon, as its energy infrastructure faces unprecedented demand from historically high electricity consumption.

The lengthy cold snap originates from a stationary polar vortex across the northern part of the continent this month, allowing bitter Arctic air to spill south. In the coming week, forecasts indicate this cold air will pull back northward slowly, permitting warmer Pacific winds to flow over America and reach into portions of southern Canada.

Pronounced Disparity with US Warmth

In stark contrast, parts of the US experienced their warmest Christmas Day on record as readings skyrocketed 15 to 30 degrees Celsius above normal. Across wide regions, the atmosphere was more akin to late spring than late December.

Several states set Christmas Day temperature records. The capital of Oklahoma soared to 25C on Christmas Day, exceeding the old record of 22C from 1982. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina were also among those that recorded temperatures above 25C.

High-Pressure System Drives the Heat

Warmer-than-normal conditions are forecast to last through Boxing Day and the days ahead, with atypical high temperatures expected to spread across the southeastern US in the coming days.

The unseasonable temperatures are powered by a robust atmospheric ridge extending from the desert south-west towards the north and east, which generates a heat-dome phenomenon. This setup creates an extensive zone of high atmospheric pressure blanketing a significant part of the landmass, which holds warm air close to the ground. Descending air compresses and adiabatically warms, fostering the buildup of exceptional warmth.