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Watch: AST1 group witnesses Size 2 avalanche on Blackcomb Mountain

With Whistler’s shallow, weak snowpack, avalanche forecaster recommends practising ‘avoidance and patience’ in the backcountry for now

Footage courtesy of Abe Churko. Warning: video contains explicit language.

When Abe Churko looked up and noticed the cloud of snow approaching, the first image that came to mind was the massive, deadly avalanche that swept into Mount Everest Base Camp in 2015, as shown in the Netflix documentary Aftershock: Everest and the Nepal Earthquake.

“You know, the one where everyone was, like, slowly watching it come down and before they know it, it just takes them all out? That was my thought,” said Churko.

The 23-year-old was in the Blackcomb slackcountry for Day 1 of his AST1 (Avalanche Skills Training Level 1) course on Saturday, Dec. 10. He and seven other students had spent the day getting familiar with transceivers and learning some probing and shovelling techniques when they noticed a mass of snow falling under the DOA couloir shortly before 3 p.m. Any fears for their safety were immediately squashed when Churko’s instructor assured the group they were in a protected zone, on top of a hill the slide wouldn’t be able to travel up.

The Size 2 slide ultimately came to a stop at a distance, near the bottom of the slope. It was nowhere near comparable to the Everest avalanche, Churko said, but even just the cloud of snow dust that “engulfed” the group “was really kind of eye-opening.”

He added, “I'm up there trying to learn how to do these procedures properly and it was almost like being thrown into the deep end.”

Churko said a group of six skied down the line following the avalanche and confirmed nobody was caught in the slide. “When they came down, they said ‘that's why you always do a ski cut,’” he explained.

According to a report on Avalanche Canada’s public Mountain Information Network, the avalanche started as a Size 1 just above a cliff band below the couloir, before triggering two secondary releases—“one directly below the aforementioned cliff band and the other closer to the bottom of the usual ski out,” the post reads. The submission’s author estimated the releases to be about 10 metres wide and 30 centimetres deep, and about 200 metres from the crown to the toe of the debris field.

'This is not a period in time when we would want to encourage folks [in Whistler] to ski big terrain with big consequences,' says Avalanche Canada forecaster

The DOA avalanche was one of several reported in the Sea to Sky corridor over the weekend. Both human-triggered and natural slides were observed following Friday’s snowstorm, while “some explosive control produced persistent slab avalanches that failed on the mid-Nov[ember] crust down about 50cm and propagated around 50m wide,” according to Avalanche Canada.

The shallow, soft snowpack resulting from Whistler’s cold, dry start to winter currently has more in common with faceted snowpacks typically seen in the Purcells or Rockies than on the coast, said Avalanche Canada forecaster Tyson Rettie. 

“A shallow snowpack is a weaker snowpack,” he explained.

The weak snowpack means instabilities like the aforementioned crust—which is buried about halfway down the snowpack and features a layer of fragile surface hoar throughout much of the Sea to Sky—often react sporadically, making it difficult to gauge where that layer will be triggered, said Rettie.

That instability isn’t expected to heal anytime soon.

 A storm anticipated to hit over this weekend could bring more than 40 millimetres of precipitation and moderate-to-strong southwest winds to the corridor. After a few days of clear skies, those conditions could prompt “an increase in both likelihood of human-triggering of avalanches and the size of avalanches that people are able to trigger,” Rettie said in an interview on Tuesday, Dec. 13.

“You're going to see a lot of new load deposited on that cold, shallow, fragile snowpack,” he explained. “As we look into the future, we're definitely not seeing a situation where conditions are going to improve significantly. This sort of waiting game; this time of self-control is likely to prolong into the future.”

When will that instability stop causing problems? After a rain event large enough to saturate the snowpack, essentially melting that layer, or when temperatures and snowfall return to more seasonal levels, burying that layer deep enough within the snowpack to go dormant.  

For now, “This is not a period in time when we would want to encourage folks to ski big terrain with big consequences,” said Rettie. “This is a time when we would encourage people to exercise self-control and play the avoidance game, but also, when you're looking at slopes, really consider the consequences of being involved in an avalanche in that terrain and put extra thought into terrain traps—is there a gully in the run-out, a road, creek, crevasse? Something to that effect, something that's going to increase the consequences of being caught in an avalanche.”

As for Churko, he said his front-row seat to Saturday’s slide hasn’t quelled his desire to head outside of the ski-area boundary, but did instil a healthy dose of respect for the risks associated with spending time in the backcountry.

“I think I needed it, to be honest with you. I’m a little but too gung ho sometimes for my own good,” he said with a laugh.