Western Canada heat wave accelerates rate of glacier melt, experts say

Click to play video: 'Is this the new normal? The science behind western North America’s historic heat wave'
Is this the new normal? The science behind western North America’s historic heat wave
As a dangerous heat dome continues to scorch western North America, climate scientists are increasingly concerned about how much more frequently we could endure extreme weather events like this. Global National's Dawna Friesen speaks with Stanford University climate scientist Noah Diffenbaugh about the effects of global heating and whether or not it's too late to temper them. – Jun 28, 2021

A sizzling heat wave during the last week of June in Western Canada left little unsinged, including fragile glaciers that are already melting at an accelerated pace, experts say.

Dozens of temperature records were shattered during the period, including a Canadian record of 49.6 C in Lytton, B.C., the day before fire destroyed most of the community.

Brian Menounos, the Canada Research Chair in glacier change at the University of Northern British Columbia, said even at elevations of 3,000 metres, it was about six degrees above average.

“Warmer than anything we’ve seen, so it was clearly a warm, quite a warm event.”

Click to play video: 'How a heat dome is causing record breaking temperatures in Western Canada'
How a heat dome is causing record breaking temperatures in Western Canada

He and other scientists are working on quantifying the glacier melt caused by the heat wave, Menounos said.

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Most of the glaciers in Alberta and B.C. mountains “haven’t been in a good state” and are projected to disappear by the end of the century due to greenhouse gas emissions and climate change caused by human activity, he said.

Jeffrey Kavanaugh, an associate professor from the faculty of science at the University of Alberta, estimated the ice melt during June’s so-called heat dome on the Wapta icefield was three times what was normal over the past dozen years. The Wapta icefield is the source of the Bow glacier and river.

Click to play video: 'Snowpack above average for Bow River basin'
Snowpack above average for Bow River basin

He looked at data from June 25 through July 4, and compared it with temperatures for the same interval over the previous 12 years.

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The temperature only dipped below zero once in that time; all other nights it remained as high as 7.5 C.

“Because the increased melt during the heat dome event melted away the snowpack in many places and exposed glacier ice, this changed the melt rate for the rest of the summer,” Kavanaugh said.

“Even if temperatures are normal, we’ll still see more melt the rest of the summer than we would have otherwise. It’s an impact that will carry on at least until the snow falls and covers the glaciers again.”

Click to play video: 'The impact of melting glaciers on Alberta’s water supply'
The impact of melting glaciers on Alberta’s water supply

Menounos said the heat coincided with the summer solstice, when the northern hemisphere gets the “maximum energy” from the sun.

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Smoke from the hundreds of fires burning in the province is an added problem, with soot that increases melting and a smoke cover that reduces sunlight but also traps heat to increase thawing of glaciers, he said.

“It’s a complicated research topic that many people are starting to study and try to better understand,” Menounos added.

This rate of glacier melt is usually seen in late July and August, he said.

Glaciers will see a “longer melt season” if temperatures continue to remain above normal, he noted.

“Glaciologists are concerned any time you get conditions that are going to sustain melt for, you know, substantial amounts of time.”


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