A prolonged deep freeze has enveloped an intense and prolonged cold spell, with readings persisting from 20 to 40 degrees below zero for multiple weeks. This week, the Yukon community of Braeburn saw the mercury drop to -55.7C, marking its chilliest December reading in nearly five decades.
Prolonged Freeze in the Deep Minus Forties
Similarly, the communities of Mayo and Dawson experienced sixteen nights in a row below -40C, with the temperature in Mayo bottoming out at -50.4 degrees Celsius earlier this week. The capital, Whitehorse, likewise saw 10 nights when the cold dipped under -30 Celsius.
The bitter chill extended its reach south over the festive period. Christmas night saw Edmonton's temperatures plummet below minus 28C.
December 26th was anticipated to usher in readings no higher than -20 Celsius in numerous areas, including Edmonton, Montreal, Ottawa and Quebec.
Likely to Linger For Days to Come
The severe cold is forecast to persist into the new year. 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 Arctic vortex settling 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 slowly, permitting warmer Pacific winds to flow over America and reach into portions of southern Canada.
Pronounced Disparity Compared to Stateside Temperatures
In stark contrast, parts of the US experienced 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 than late December.
A number of states broke historical records for December 25th warmth. In Oklahoma, Oklahoma City hit 25C on Tuesday, exceeding the old record of 22C from 1982. Metropolitan areas such as Austin, Dallas, and Charlotte also logged readings above 25 degrees Celsius.
High-Pressure System Fuels Warmth
Above-average warmth is expected to continue on December 26th and into the weekend, with unseasonable heat forecast to sweep through the American Southeast soon.
This heat is being driven by a strong upper-level ridge stretching from the southwestern deserts northward and eastward, creating a heat-dome effect. This setup creates an extensive zone of high atmospheric pressure blanketing a significant part of the landmass, effectively capping warm air at lower altitudes. Sinking atmospheric air undergoes compression and additional heating, enabling abnormally high temperatures to develop.
