Four backcountry skiers had their destination in sight last Saturday afternoon when a wind slab took their group for a brief but buckling slide, burying one who was quickly rescued without injury.
A Mountain Information Network (MIN) report shared with Avalanche Canada recounted that the group had been 500 metres away from the Asulkan Cabin in Glacier National Park on Jan. 10 when the leader triggered a wind slab avalanche down the sheltered left side of the slope they were ascending along.
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“The first person in the group was knocked over and carried approximately five meters downslope,” the report details. “They were majority buried except for one arm. They were able to breathe normally.”
Their two companions directly behind also got snagged by the slab to a lesser extent, dragged down to their knees in snow but left standing.
With the final skier unimpacted and the middle two still able to move, they swiftly performed a rescue to extract their buried companion, reporting no injuries.
“After, the group turned around and followed their skin track back down into the sheltered areas of the tree triangle,” the report adds.
This type of slab forms when wind blows a dense layer of snow over weaker snowpack. According to Avalanche Canada, the best way to manage wind slabs is to look and feel for them.
“Watch for blowing snow and see where it is being transported,” the non-profit organization advises. “Wind-loaded areas generally appear more rounded, smooth, and pillow-like. The snow will also feel noticeably stiffer under your feet or machine and you may even hear hollow or drum-like sounds on very hard wind slabs.”
Beyond Saturday’s incident in the Asulkan Valley, Avalanche Canada is cautioning backcountry users in Rogers Pass as unanticipated warmer weather, combined with leftover snow from recent storm activity, elevates danger levels.
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This includes a higher risk for storm slabs, which it says can subsequently displace weaker snowpack layers and trigger larger avalanches. When exposed to sunlight, along areas such as Frequent Flyer and Connaught Creek, the slabs will be sensitive to skiers.
“Ski operations neighbouring Rogers Pass report storm slabs being triggered both naturally and by humans to Size 2,” Avalanche Canada writes.
Skiers can check drivebc.ca for road closures and conditions, and visit avalanche.ca for the latest MIN reports.