Avalanche forecast

Summit Lake

Chugach National Forest Avalanche Center
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Avalanche danger

Sun
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1.5–2.5

    Recent avalanches: We observed a widespread natural avalanche cycle, including very wide-propagating avalanches on Fresno, Raven, Butch, Tri-Tip, Templeton, and Summit Peak. There were multiple very large human-triggered avalanches in Girdwood, Turnagain Pass, and Seward, but none that we have heard of so far in the Summit Lake zone.

    This weekend has us on edge. We're on the heels of a major loading event on top of a problematic snowpack, we just witnessed a very impressive natural cycle, and people have already triggered very large avalanches from flat terrain. All of this is a recipe for an avalanche accident, and we are urging everyone to recognize the severity of the current conditions. Travel in and below avalanche terrain is not recommended today.

    Conditions are touchy right now due to the magnitude of the recent storm combined with poor snowpack structure beneath the new snow. Summit Lake recorded 1.5' new snow equalling 1.7" snow water equivalent (SWE). This came in with extreme easterly winds, which briefly changed directions yesterday afternoon, effectively loading all aspects within the past 24 hours. All of this new and windblown snow is adding a lot of weight to a weak layer of advanced facets, now buried 2 to 4' deep or deeper. The layer was very reactive ahead of this storm and has now been pushed to its breaking point. Based on the human-triggered avalanches yesterday, we are seeing clear signs that this layer is seriously concerning.

    The only way to manage this problem is to avoid traveling on or below steep slopes.  This is not a typical storm snow issue that will improve in a day or two—it will take time to heal.

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    1–2

    The new and windblown snow from the past three days is expected to remain reactive today. Though it will likely be slightly more stubborn than it was yesterday, it is still likely a person will be able to trigger a big avalanche, even if it doesn't impact the deeper weak layers discussed in Problem 1 above. This storm came in warm and wet, dropping 2 to 4' of heavy snow on top of the dry, low-density surface that existed before the storm.

    Winds have remained strong since it stopped snowing, and there is likely a fresh round of touchy wind slabs that have formed. These may have formed further downslope than we often see, which is another out-of-the-ordinary pattern making conditions unusually dangerous today. While this adds complexity to the avalanche equation, the terrain management is simple: avoid traveling in avalanche terrain for now.

    Upper elevation estimated storm totals since Wednesday night are listed below:

       Snowfall   Snow Water Equivalent (SWE)  Girdwood  3-4'  3.8  Portage  2-4'  3.8  Turnagain  1.5-2'  1.6  Summit  1.5'  1.7  Seward  2-3'  3.1

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