An intense cold spell has seized a severe and lengthy Arctic outbreak, with temperatures hovering 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, representing its most frigid December day in half a century.
Enduring Chill Below -40C
In addition, the locales of Mayo and Dawson suffered through over two straight weeks of nights below -40C, with Mayo experiencing a low of -50.4C at the start of the week. Whitehorse also recorded ten separate nights when the cold dipped under -30 Celsius.
This Arctic air mass pushed further southward through Christmas week. Christmas night saw Edmonton's temperatures plummet below minus 28C.
Boxing Day was expected to bring readings no higher than -20 Celsius through a wide swath, from Edmonton in the west to Quebec in the east.
Expected to Continue For Days to Come
This harsh winter weather is expected to continue into the new year. There are warnings of possible electrical grid strain in Yukon territory soon, as the territory’s power grid comes under strain from historically high electricity consumption.
This extended freeze is the result of the Arctic vortex settling across the northern part of the continent this month, enabling a surge of icy Arctic winds to descend. 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.
Stark Contrast to American Heat
In stark contrast, parts of the US experienced their warmest Christmas Day on record as readings skyrocketed 15 to 30 degrees Celsius above normal. 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. Oklahoma City, Oklahoma, reached 25 degrees Celsius on Christmas, surpassing the previous peak of 22C set in 1982. Metropolitan areas such as Austin, Dallas, and Charlotte similarly saw thermometers rise past the 25C mark.
High-Pressure System Drives the Heat
Above-average warmth is expected to continue on December 26th and into the weekend, with atypical high temperatures expected to spread into the south-eastern states later in the week.
This heat is being driven by a robust atmospheric ridge extending from the desert south-west towards the north and east, establishing a classic heat-dome pattern. This pattern establishes a broad area of high pressure across much of the continent, trapping warm air near the surface. As air sinks through the atmosphere, it compresses and heats further, fostering the buildup of exceptional warmth.
