Deep Freeze Grips the Great White North as US Records Warmest Christmas in History.
An intense cold spell has seized a bitter and extended period of frigid weather, with thermometers lingering between -20C and -40C for multiple weeks. A reading of -55.7 Celsius was logged in Braeburn, Yukon, on Tuesday, representing its most frigid December day in nearly five decades.
Consecutive Nights Below -40C
In addition, the locales of Mayo and Dawson suffered through 16 consecutive nights colder than minus 40 degrees, with Mayo experiencing a low of -50.4C at the start of the week. Whitehorse similarly reported ten separate nights when the cold dipped under -30 Celsius.
The bitter chill extended its reach south during the holiday season. Christmas night saw Edmonton's temperatures plummet below minus 28C.
The day after Christmas was forecast to deliver lows of at least -20C through a wide swath, from Edmonton in the west to Quebec in the east.
Likely to Linger For Days to Come
The frigid conditions are predicted to linger through the start of January. There are warnings of possible electrical grid strain in Yukon territory over the next several days, as the system endures record-high pressure from peak power usage levels.
The lengthy cold snap originates from the polar vortex remaining anchored across the northern part of the continent this month, which funnels frigid northern air southward. In the coming week, forecasts indicate this cold air will pull back northward gradually, enabling milder Pacific air to move across America and reach into portions of southern Canada.
Stark Contrast with US Warmth
Conversely, sections of America recorded their warmest Christmas Day on record as readings skyrocketed 15 to 30 degrees Celsius above normal. In many areas, conditions felt more typical of April or May than late December.
A number of states broke historical records for December 25th warmth. The capital of Oklahoma soared to 25C on Christmas Day, topping the prior high mark of 22 degrees established over forty years ago. Cities including Austin and Dallas, in Texas, and Charlotte, North Carolina similarly saw thermometers rise past the 25C mark.
High-Pressure System Drives the Heat
Warmer-than-normal conditions are forecast to last on December 26th and into the weekend, with atypical high temperatures expected to spread through the American Southeast soon.
The warmth has been fuelled by a powerful high-altitude ridge extending from the desert south-west towards the north and east, creating a heat-dome effect. Such a configuration results in a widespread high-pressure system across much of the continent, trapping warm air near the surface. Descending air compresses and adiabatically warms, fostering the buildup of exceptional warmth.
