Records have toppled far and wide across the Intermountain West, the interior Pacific Northwest, and especially western Canada.
According to the Washington Post, we can blame the abnormally high temperatures in Alberta, Saskatchewan, Manitoba, the Northwest Territories, and even Nunavut on something called an “omega block.”
Named for the jet stream’s likeness to the Greek letter omega (Ω), these blocking ridges lock weather in place, leading to extended periods of hot and dry conditions, according to Terri Lang, a meteorologist with Environment and Climate Change Canada.
This resulted in a number of heat records being broken in Canada’s western communities, including in a town in the Northwest Territories, where the temperature was much hotter than in many cities located much further south, and high enough to break a 125-year-old record.
On Thursday, Environment Canada issued a heat warning for portions of northern Alberta including the communities of Edmonton, Fort McMurray and Athabasca. The early heat and lack of rain have already ignited three grassfires outside Edmonton this week, CTV News is reporting.
Calgary broke a heat record that had been set in 1897, with a high of 27.3 C (81.1 F) on Wednesday. The community typically sees averages of around 15 C in early May.
Perhaps the most extreme was a 31.1 C (88 F) reading in Hay River, Northwest Territories, where highs should be in the lower to mid-50s this time of year. Hay River is located at about 60.5 degrees north latitude, about as far north as Helsinki, Anchorage, or Reykjavik, Iceland. It’s about 430 miles south of the Arctic Circle.
“The Prairies are pretty much blocked from getting precipitation under this pattern,” Lang said. “Underneath a high-pressure system like this, the air sinks. And when air is forced to sink, it warms. So we’re getting extra warmth.”
Although omega blocks and early spring heat are not unprecedented, Lang said this extent of record-breaking heat does stand out. “This is sort of a very rare event for it to be occurring this early in the season, and just a little bit of that weather whiplash too.”
