Deep Freeze Envelops the Great White North as America Sees Most Unseasonably Mild Christmas in History.
An intense cold spell has seized an intense and prolonged cold spell, with readings persisting in the minus 20 to minus 40 Celsius range for multiple weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, marking its chilliest December reading since 1975.
Enduring Chill of Extreme Cold
Meanwhile, Mayo and Dawson endured over two straight weeks of nights below -40C, with the temperature in Mayo bottoming out at -50.4 degrees Celsius on Monday. The capital, Whitehorse, likewise saw 10 nights when readings fell to minus 30 degrees or lower.
The deep freeze spread farther south over the festive period. On Christmas Day, overnight temperatures in Edmonton fell below -28C.
Boxing Day was expected to bring lows of at least -20C through a wide swath, from Edmonton in the west to Quebec in the east.
Forecast to Persist For Days to Come
The frigid conditions are predicted to linger into the new year. Authorities have cautioned about potential power failures in the Yukon in the coming days, as the territory’s power grid comes under strain from record-high energy demand.
The prolonged chill has been caused by the Arctic vortex settling over Canada for much of December, enabling a surge of icy Arctic winds to descend. In the coming week, forecasts indicate this cold air will pull back northward gradually, enabling milder Pacific air to move across the United States and penetrate southern Canadian regions.
Pronounced Disparity Compared to Stateside Temperatures
Conversely, sections of America recorded historically high temperatures for Christmas as temperatures soared about 15-30C above the seasonal average. 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
Unseasonable heat is predicted to persist for the remainder of the week and beyond, with unseasonable heat forecast to sweep into the south-eastern states later in the week.
This heat is being driven by a powerful high-altitude ridge extending from the desert south-west towards the north and east, which generates a heat-dome phenomenon. Such a configuration results in a widespread high-pressure system blanketing a significant part of the landmass, effectively capping warm air at lower altitudes. Descending air compresses and adiabatically warms, allowing unusually warm temperatures to build.
