Turnagain Pass

No recent avalanches were reported yesterday. Glide avalanches on Sunburst, Penguin Ridge, and Seattle Ridge from Wednesday and Thursday are the most recent known avalanches.

Glide avalanches continue to release across the forecast area, causing very large and destructive avalanches 4-6′ deep on commonly traveled routes. While it is normal for us to have occasional glide avalanches throughout the winter during most seasons, the past few weeks have been unique because of the frequency of glide avalanches and how widespread glide cracks are. A few notable events include a glide release on the Repeat Offender slide path which threatens the motorized uptrack on Seattle Ridge, one just below the normal skin track on Sunburst, and an older release on the SW face of Cornbiscuit. Just because these areas have already had glide avalanches does not mean that they are safe now. Many areas still have widespread glide cracks above popular routes, which can spontaneously release at any time.

The best way to manage this unique avalanche hazard is to avoid spending time underneath glide cracks. This is easier said than done on days like today where poor visibility can obscure your ability to see the slopes above you. If you find yourself needing to travel under a glide crack, try to minimize your time on that slope and spread out your group so you are not all exposed at the same time. The randomness and huge destructive potential of glide avalanches make them a scary hazard.

Strong winds Friday morning likely formed wind slabs 1-2′ deep along upper elevation ridgelines that could still be possible for a person to trigger. Today the winds will start off light but are expected to increase throughout the day and return to averages of 20-30 mph and gusts to 50 mph out of the E by this afternoon. This fresh round of winds will build another generation of wind slabs roughly 1′ deep at upper elevations. To avoid accidentally triggering a wind slab keep an eye out for active wind transport along ridgelines, shooting cracks, and hollow or drum like snow. Jumping on small, steep slopes can be a good way to determine how reactive wind slabs are.

It’s been almost a week since the last big storm triggered a cycle of large avalanches that we believe failed on a weak layer of facets and surface hoar that was buried on January 2nd. The only human triggered avalanche we know of on this layer was in Main Bowl on Seattle ridge and was remotely triggered by a group of snowmachiners riding along the adjacent ridge. Observations from across the region this week have hinted that the distribution of the Jan. 2 buried surface hoar is spotty. On isolated slopes where the buried surface hoar remains intact it could still be possible to trigger an avalanche 2-4′ deep. This is most likely in sheltered bowls and areas that have not seen much traffic in recent days like Lynx Creek, Silvertip, or Johnson Pass. Due to the depth of the weak layer it is difficult to assess without stopping to dig a snowpit. Stability tests like a compression test (CT) or extended column test (ECT) can be useful to determine if there is a concerning buried weak layer in the area you are travelling, especially if you get propagation across your column in an ECT.

Forecaster Daniel Krueger conducting a crown profile on the avalanche that was remotely triggered in Main Bowl on January 8th, 2024. Photo 1.9.24