🔗 Share this article

Northern Canada has been gripped by a severe and lengthy Arctic outbreak, with readings persisting in the minus 20 to minus 40 Celsius range for an extended duration. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, marking its chilliest December reading since 1975.

Consecutive Nights in the Deep Minus Forties

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 experiencing a low of -50.4C on Monday. The capital, Whitehorse, likewise saw a series of ten nights when temperatures dropped below -30C.

The deep freeze spread farther south over the festive period. Christmas night saw Edmonton's temperatures plummet below minus 28C.

The day after Christmas was forecast to deliver readings no higher than -20 Celsius across many regions, encompassing cities from Edmonton to Quebec.

Expected to Continue For Days to Come

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

This extended freeze is the result of the polar vortex remaining anchored over Canada for much of December, which funnels frigid northern air southward. 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.

Pronounced Disparity to American Heat

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 rather than the end of December.

Several states set Christmas Day temperature records. In Oklahoma, Oklahoma City hit 25C on Tuesday, topping the prior high mark of 22 degrees established over forty years ago. Urban centers like Austin, Dallas, and Charlotte, North Carolina were also among those that recorded temperatures above 25C.

Heat-Dome Effect Fuels Warmth

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.

The warmth has been fuelled by a powerful high-altitude ridge reaching from the arid southwest across the continent, establishing a classic heat-dome pattern. This pattern establishes a broad area of high pressure over a large portion of North America, effectively capping warm air at lower altitudes. Descending air compresses and adiabatically warms, allowing unusually warm temperatures to build.