Avalanche forecast

Summit Lake

Chugach National Forest Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

With springtime temperatures and sun this week we have seen an uptick in glide avalanches releasing naturally in the Summit Lake area. These very large and destructive avalanches are unpredictable and the best way to manage them is to avoid traveling under slopes with glide cracks. We also continue to monitor a buried weak layer about 1 to 2' deep that has the potential to cause large human triggered avalanches. To avoid this weak layer you can stick to low angle terrain or to reduce your exposure you can avoid traveling on slopes with terrain traps below. 

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SPECIAL ANNOUNCEMENT

Sean Sullivan, Cory Davis, and Travis Temple will be hosting a free avalanche awareness and rescue training event in memory of Tucker Challans on Saturday, March 29, at Alaska West Air in Nikiski. See the flyer in the media gallery below for more information.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Our main concern continues to be human triggered avalanches on a layer of buried surface hoar about 1 to 2' deep in the Summit Lake Area. This is the same weak layer involved in the fatal avalanche accident on Seattle Ridge last Saturday. While we haven't seen much avalanche activity on the buried surface hoar in Summit Lake, we have found several areas where the layer exists and has produced large shooting cracks and collapsing. These red flags are a clear sign that avalanches are possible in areas where the weak layer is preserved, which is most likely above 2000' in areas sheltered from the wind like spare forested terrain near treeline.

    To identify concerning areas keep a close eye out for shooting cracks and collapsing as obvious clues that the weak layer is sensitive to human triggering. Using hand pits and snowpits to assess the snowpack seems more reliable in Summit Lake because the layer is not buried as deeply. However, adopting a conservative mindset and choosing terrain with safe runouts is a good way to add some extra safety margin. To avoid this issue altogether you can always stick to low angle terrain and avoid slopes with steep terrain overhead.

    Example of buried surface hoar about 1' deep from Raven Ridge.

    Photo: John Sykes

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    The combination of warm temperatures and partly sunny skies the past few days has accelerated the transition to a spring snowpack. Across the region, an uptick in glide avalanche activity over the past few days is another sign that the snowpack is feeling the effects of the spring weather. Glide avalanches have been on our radar throughout the season, but the notable uptick in glide avalanche activity is a good reminder to carefully scan slopes above for signs of glide cracks and try to avoid spending time underneath. These massive avalanches release randomly and would be very dangerous to be caught in. 

    Wet loose avalanches have also been releasing naturally on steep solar aspects (east, south, west) as they heat up later in the day. This might not be as prominent today if cloudy conditions prevail, but depending on how thick the cloud layer is greenhouse effect can heat up the snowpack even without direct sun. On big slopes, wet loose avalanches can grow large as they run downhill and create a large debris pile if they run far.

    Cornice fall is another normal part of the transition to a spring snowpack and can happen randomly while cornices are heating up in the sun. Today is expected to be cloudier than the past few days, but it is still good practice to avoid spending time underneath cornices and give them a wide berth when traveling along ridgelines.

    (3/27/2025)

    Multiple large avalanches on the south face of Wilson South Mtn. 

    Photo: Daniel Krueger

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