Temperature records in Canada and the north-west US have been smashed again, as a historic heatwave in the region lifts maximums up to 20 degrees above average.
“It’s really, really extreme,” said Andrew King from Melbourne University’s ARC Centre of Excellence for Climate Extremes.
“The records are being surpassed by quite a long way with this heatwave, in some cases by two or three degrees Celsius above previous records.”
Lytton in British Columbia reached a record 47.9 degrees on Monday, more than two degrees hotter than Canada’s former highest temperature, which, until this week, stood for 84 years.
“To beat a national record by 2.5 degrees is, frankly, statistically freaky,” Bureau of Meteorology senior climatologist Andrew Watkins said on Twitter.
By comparison, 47.9 degrees is hotter than any temperature recorded in Alice Springs (45.7 degrees) or the notoriously hot US desert city of Las Vegas (47.2 degrees).
Lytton is about 100 kilometres from the Whistler Blackcomb ski resort and is at a latitude of 50 degrees north — closer to the North Pole than the equator.
Records fall on both sides of border
In the US, Portland, a typically cool, wet city in the Pacific North-West, reached 46.6 degrees on Monday; that’s five degrees above a record that until this heatwave stood for more than 50 years.
“It’s just breaking records left, right and centre,” said Portland-based Australian climate scientist Cassandra Rogers.
Dr Rogers moved from Melbourne to Portland in 2019 to study heatwaves.
This week, she and her colleagues at Washington State University found themselves in the middle of one of the worst heatwaves on record.
“One scientist in particular who’s lived here for a number of years, he said he just never thought these conditions would happen in certain parts of Oregon,” she said.
“He just never expected temperatures would get that high.”
Multiple factors had aligned to produce the unprecedented temperatures, Dr Rogers said.
“There’s a really unusually high pressure system that’s trapping a lot of heat.
“Heatwaves like this event are also often worse due to the impact of climate change.
“Climate change has increased the frequency of heatwaves; it’s increased how hot heatwaves get and increased how large [geographically] they get.”
On top of all of that, Dr Rogers said, there was a drought in the Pacific North-West that had reduced the amount of moisture available to cool the atmosphere through evaporation.
Heat buckles infrastructure
Dr Rogers said despite a huge effort to prepare Portland for the heatwave, unexpected impacts were popping up across the city.
“The main freeway up the West Coast, from California up to Seattle, that’s buckled and cracked,” she said.
“The train service in Portland closed down today because one of the power cables melted or burst.
“Swimming pools, somewhere where you might want to go to cool down, have restricted how many people go in because they don’t have enough lifeguards.
“There’s been a couple of drownings because people have gone to the water to cool down … the water here is ice pack melt. It’s early June and the water is really, really cold.”
Wildlife not adapted to high temperatures
While humans could adapt to some degree to these temperatures through technology, wildlife had not, Dr Rogers said.
“They’ve had problems with salmon die-off in the past with high temperatures here.”
In 2015, extreme heat and low streamflow killed 99 per cent of salmon migrating through the Columbia and Snake rivers in the Pacific Northwest.
In Portland this week, even urban wildlife has struggled.
“I’ve seen squirrels outside the window here and in the evening they will lie flat on their stomach to cool down,” Dr Rogers said.
The heatwave is far from over – the forecast maximum temperature for Lytton on Tuesday was 47 degrees.