Turnagain Pass Avalanche Forecast

After a sunny weekend of generally stable conditions the weather change today is not expected to affect the avalanche danger, as not much snow or wind is forecast. However, it will be important to pay attention if conditions change. The snow surfaces are not ideal for new snow bonding to the old snow. This will become a real concern when we do get snow accumulation.

Finding an isolated slab especially in upper elevation terrain in Girdwood, Portage or Placer is not completely out of the question. This part of the advisory area received more snow in the last storm. There has been one known human triggered avalanche that failed in the facets below the new snow, which was last Thursday in the Placer Valley. With colder temperatures and no additional loading observations and snowpack tests have been pointing towards a stable snowpack. 

Low danger does not mean no danger. Practice good travel habits, such as exposing one person at a time, watching your partners and grouping up in safe zones are key ways to minimize risk. Ease into steep terrain and factor in the consequences should you encounter one of the following:

• An outlier slab avalanche: 
  • Triggering a slab avalanche would most likely occur on an exposed ‘unsupported slope’ that sits above a cliff or steep rocky terrain. An old wind slab or a pocket of buried near surface facets and/or surface hoar 5″-2′ below the surface may be lurking in an isolated area.
• Glide avalanche:  
  • Identify glide cracks and avoid spending any time under these features. Glide avalanches are completely unpredictable and not human triggered.
• Cornice fall: 
  • Remember cornices often break farther back from ridges than expected. Give them a wide berth.
• Loose Snow avalanche (sluff):
  • Be aware of fast moving surface snow in steep terrain. 

The next buried weak layer??? Surface hoar on a melt-freeze crust, 1-19-19. Photo: Troy Tempel

South of Turnagain – Johnson Pass/Summit Lake zone: A poor snowpack structure exists in these areas.  Multiple mid-pack weak layers of facets and buried surface hoar have been found as well as a facet/crust combination in the bottom of the snowpack. No recent avalanche activity and calm weather has allowed the pack to slowly adjust. However, it still important to evaluate the terrain and snowpack. Upper elevation terrain with hard, wind-affected snow over the buried weak layers is the most suspect.