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A prolonged deep freeze has enveloped a severe and lengthy Arctic outbreak, with thermometers lingering from 20 to 40 degrees below zero for multiple weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, representing its most frigid December day in half a century.

Enduring Chill of Extreme Cold

In addition, the locales of Mayo and Dawson suffered through 16 consecutive nights dipping under the minus 40 Celsius threshold, with Mayo plunging to -50.4C on Monday. The capital, Whitehorse, likewise saw ten separate nights when the cold dipped under -30 Celsius.

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 through a wide swath, encompassing cities from Edmonton to Quebec.

Forecast to Persist Through Early January

The frigid conditions are predicted to linger for the foreseeable future. Officials have warned that the Yukon could face electricity outages soon, as the territory’s power grid comes under strain from record-high energy demand.

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. Next week, the cold air mass is expected to retreat north gradually, enabling milder Pacific air to move across the US and into parts of southern Canada.

Stark Contrast with US Warmth

Conversely, sections of America recorded 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 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.

Atmospheric Ridge Sustains High Temperatures

Warmer-than-normal conditions are forecast to last through Boxing Day and the days ahead, with unseasonable heat forecast to sweep across the southeastern US in the coming days.

The unseasonable temperatures are powered by a strong upper-level ridge reaching from the arid southwest across the continent, which generates a heat-dome phenomenon. Such a configuration results in a widespread high-pressure system across much of the continent, which holds warm air close to the ground. Sinking atmospheric air undergoes compression and additional heating, allowing unusually warm temperatures to build.