“Rotten Rock”: Climate change is changing the face of Canadian mountaineering

For decades, the Abbot Pass Hut stood in a rugged saddle between two prominent peaks, overlooking the clear turquoise of Lake Louise in Banff National Park – a destination for mountaineers from all over the world until the ground beneath it melted and it had to be closed.

Researchers at the University of Calgary have now used a century's worth of hut logbook entries to shed light on how climate change is wiping out historic climbs, making others more dangerous and changing the face of Canadian mountaineering.

“There were definitely comments about how climate change has affected the Canadian Rockies, and many cabin visitors expressed sadness and concern about this,” wrote Kate Hanly, a geography doctoral student and co-author of a paper based on these logs published in the journal Climatic Change.

“Climate change is contributing to changing mountaineering conditions in the Canadian Rockies,” she says in an email.

Mountain guides agree.

“Classic routes have changed,” says Paul Vidalin, president of the Association of Canadian Mountain Guides and 25 years of experience as a mountain guide.

“In some places the ice has disappeared and there is nothing left but rotten rock. What used to be beautiful, gentle glacier slopes are now full of crevasses.”

James Gudjonson, vice president of the Alpine Club of Canada, has been a mountaineering and ski guide for 30 years.

“It's really disheartening,” he says. “You know a lot of (routes) have disappeared or are slowly disappearing and not coming back.”

Hanly's article combines 6,283 alpinist trip reports from the Abbot Pass hut logbook with those from a modern mountaineering database. It covers the period from 1923 to 2024.

Early entries describe reliable ramps of packed snow on the way to famous peaks such as Mount Lefroy and Mount Victoria.

Yet by 2017, all climbers at Lefroy reported exposed ice and semi-bare, unstable rock. Five percent of climbers in Victoria reported bare rock in the 1950s, while more than half did so between 2013 and 2022.

This boulder represents more than just a shaky footing. If the ice holding it in place melts, it will fall.

On a route to Abbot – used since the beginning of the last century – there were no reports of dangerous rockfall in the first 50 years of the hut's records. In the last decade, three quarters of climbing parties mentioned it.

Similar results were obtained on another route to the hut.

“The typical right side was a rockfall war zone with many near misses,” said one entry from 2009.

The dangers are not limited to Abbot Pass, says Christoph Dietzfelbinger, who has worked as a mountain guide in British Columbia's Coast Range since the 1980s.

“The access to the summit ridge on Mount Edziza used to be a simple snow slope,” he says in an email. “Today it is a 30- to 70-meter-high slope of black water ice that requires full alpine ice equipment.”

In the Bugaboos Mountains south of Golden, British Columbia, a popular saddle in perhaps Canada's most famous climbing area is becoming increasingly inaccessible due to snow loss.

“I think at some point it will become a place where people just don't go anymore,” says Gudjonson. “It was the access point for dozens of routes.”

Other dangers are also increasing.

Reduced snow cover and increased melting are changing the shape and angle of glaciers, making them more vulnerable to avalanches. Snow bridges that allow mountaineers to safely cross crevasses are weakened.

Gudjonson observed this effect on the Wapta Icefield, a popular high-altitude glacier ski touring destination between Banff and Jasper in Alberta.

“There's just not as much snow because it's raining so much and the temperatures are so warm,” he says. “Bridging doesn't work as well.”

“In summer it's OK – you can see the ice. But the real problem is the thinner snow cover in winter.”

In addition, areas that normally have deep, stable snowpacks are now experiencing large amounts of snow, followed by long periods of drought, sometimes interrupted by rain or thaw, which are causing snow layers to form and making avalanche assessment even more difficult.

“It’s more unpredictable, more extreme,” says Vidalin.

“There seem to be more layers of problems (in the snow), more variability, more complexity.”

Climate change is reducing some of the hazards. For example, the snow cornices that once hung over Victoria's southeast ridge have shrunk due to the thinner snow cover, making travel faster and easier, Hanly says.

By adapting the travel guides, new routes may emerge.

“The only constant in the guiding profession is change,” Hanly writes in the email. “I don't think we are in danger of losing the mountaineering culture in this country (at least for now), but I am pretty sure it will continue to evolve.”

There are economic consequences, Hanly adds.

“The warm and dry weather in January has limited ice climbing opportunities to the point that some guides have been out of work. In the Canadian Rockies, and particularly in the Bow Valley where so many guides operate, climate change could have a significant impact on the industry, with potentially cascading effects on the tourism and hospitality industries.”

Gudjonson points to the industry that has developed around backcountry skiing and mountaineering.

“What will happen to the commercial operators?” he asks.

But that's not his main concern. The closure of the Abbot Pass hut in 2018 haunts climbers and hikers, he says.

“We have 100 years of history and something that is woven into the culture of the mountain community. These historic places are being lost forever.”

Travel guides talk about it all the time, says Dietzfelbinger.

“There is something best called ecological grief,” he wrote. “A landscape that was dear to me and that gave me many experiences has been irrevocably changed.”

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Bob Weber, The Canadian Press