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

Northern Canada has been gripped by an intense and prolonged cold spell, with thermometers lingering in the minus 20 to minus 40 Celsius range for weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, its coldest December temperature in nearly five decades.

Enduring Chill of Extreme Cold

In addition, the locales of Mayo and Dawson suffered through over two straight weeks of nights dipping under the minus 40 Celsius threshold, with Mayo plunging to -50.4C at the start of the week. Whitehorse also recorded a series of ten nights when temperatures dropped below -30C.

The bitter chill extended its reach south over the festive period. In Edmonton, the Christmas overnight low dipped under -28 degrees Celsius.

Boxing Day was expected to bring minimum temperatures of at least minus 20C across many regions, encompassing cities from Edmonton to Quebec.

Expected to Continue into the New Year

This harsh winter weather is expected to continue for the foreseeable future. Authorities have cautioned about potential power failures in the Yukon in the coming days, as the system endures record-high pressure from peak power usage levels.

This extended freeze is the result of a stationary polar vortex above Canadian territory through December, allowing bitter Arctic air to spill south. 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 with US Warmth

In stark contrast, parts of the US experienced their warmest Christmas Day on record 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. Metropolitan areas such as Austin, Dallas, and Charlotte were also among those that recorded temperatures above 25C.

High-Pressure System Sustains High Temperatures

Warmer-than-normal conditions are forecast to last through Boxing Day and the days ahead, with abnormal warmth projected to move across the southeastern US in the coming days.

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. Such a configuration results in a widespread high-pressure system blanketing a significant part of the landmass, which holds warm air close to the ground. Sinking atmospheric air undergoes compression and additional heating, allowing unusually warm temperatures to build.