Turnagain Pass

The last reported natural activity was Saturday (1/28) when sunny skies and warm temperatures triggered wet loose avalanches that were pulling out small slabs. The last known human-triggered avalanches were 10 days ago (1/21), where multiple people were caught and carried in avalanches failing on a layer of buried surface hoar.

The layer of buried surface hoar that has been found widespread across the forecast area and was responsible for multiple human-triggered avalanches on 1/21 continues to show signs of strengthening.  It’s been 10 days now since an avalanche was triggered on this layer.  That said, this layer still exists in the top 2-3’ of our snowpack and should continue to warrant a cautious and thoughtful mindset even if the classic red flags (cracking or whumpfing) aren’t showing up in your travels.  Likely trigger points for this avalanche problem include thin spots in the slab close to rock outcroppings or wind-scoured areas.

The further we get from the 1/21 avalanche cycle without incident, the more confidence we can have that this weak layer is becoming less likely to trigger.  10 days out is nothing to bet our life on though.  It remains critical to stack the deck in our favor when choosing to recreate in the mountains in the presence of a persistent weak layer such as we have now.  How can we do this?

• Evaluate the snowpack and your chosen terrain carefully by taking the time to identify and test this weak layer. Dig a snowpit or use your snowmachine to cut small no-consequence test slopes to see how the snowpack reacts under your weight.
• Progress into steeper or more complex terrain throughout the day if signs are pointing toward trusting the snowpack. If not, dial it back.
• Pay attention to consequences. If the slope slides, are you exposed to a terrain trap such as a gully, rocks, trees, or a cliff.  Is there a clean runout?
• Expose only one at a time to avalanche terrain and ensure you and your crew are rescue ready.
• Lastly, you can avoid this problem entirely by sticking to slopes less than 30 degrees.

Density profile from Max’s Mountain (Girdwood Valley) on 01.29.2023.  Snowpit and annotation courtesy of Chugach Avy intern Megan Guinn.

The multi-talented Brooke Edwards testing and identifying our problem layer of buried surface hoar in Turnagain Pass during an Alaska Guide Collective Rec Level 1 class on 01.28.2023.  If snowpack is the question, dialing back terrain choices to less than 30 degree slopes is the answer.

If you’ve been tuning in over the past several weeks, you know that we aren’t quite ready to ignore the facet/ crust combo affectionately referred to as the Thanksgiving Crust.  Now buried 4-8’ deep this is a high consequence, low probability avalanche problem at this point.  This layer is most problematic in areas with a thinner snowpack at elevations above 2500′. Although it is unlikely a person will trigger an avalanche on a layer that deep, the consequences of getting caught would likely be fatal.