Turnagain Pass Avalanche Forecast

No known recent avalanches

The skies should trend towards clearing today with light winds and cold temperatures creating a mighty temptation to venture into bigger terrain, but dragons are lurking in our snowpack. Throughout the advisory area we have weak sugary persistent weak layers underneath 2-3′ of snow that fell over the past 10 days. As we get further away from the most recent storm the probability of human triggered avalanches is likely decreasing but the consequences if one of these persistent slabs releases could be high. To completely avoid this avalanche problem stay on lower angle slopes, smaller features, and be aware of terrain above you that could be triggered remotely.

There have not been many folks travelling in the mountains since the latest storm to test the reactivity of our weak layers, so we have some uncertainty about how sensitive they are to triggering. It is important to remember that persistent slabs are notoriously unpredictable and don’t always release with the first person on the slope. We continue to recommend careful evaluation of the snowpack by being alert to collapsing or shooting cracks and using snowpits to identify and test weak layers (small collapse on Sunburst 12.1.21). The most common weak layer setup we have seen recently is a layer of weak and sugary facets on top of a stout melt freeze crust (example here).

Motorized areas recently opened in Chugach National Forest: We have very limited information from the areas that opened to motorized access yesterday (Placer River, Johnson Pass, Lynx Creek, Lost Lake, etc). We expect that the persistent weak layers exist throughout the advisory area and recommend a conservative mindset while venturing into new terrain. If you travel into a new area please consider sending in an observation so we can start to fill in our knowledge gaps and get a better picture of the conditions throughout the area.

Wind slabs and cornices: Watch for old wind slabs and cornices that built up during the last storm, especially at higher elevations and along ridgelines.

Small avalanche in a wind loaded area on the E face of Seattle Ridge from sometime in the past two days. 12.1.21

Cornice fall in Hippy Bowl on Tincan Common from sometime during the last storm. Photo: Anonymous 12.1.21

Glide activity has continued to decline and many of the lingering glide cracks are slowly getting filled in by the recent storms. They can still be a hazard to fall into and have to potential to spontaneously release. Minimize time underneath open glide cracks to avoid this unlikely but catastrophic avalanche hazard.