Bollettino valanghe

Summit Lake

Chugach National Forest Avalanche Center
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Pericolo valanghe

Sat
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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In sintesi

Human triggered avalanches on wind loaded slopes are still a concern in some areas because of a weak layer of snow underneath. These are isolated to upper elevations and are typically found near ridgelines, rollovers, and cross-loaded gullies. There is also a very small chance of triggering a larger avalanche on buried weak layers deeper in the snowpack.

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    The same layer of buried surface hoar that is causing large and dangerous avalanches in the Turnagain Pass and Seward forecast areas also exists in Summit Lake. However, due to the general lack of recent snowfall in the area, it seems to be much less widespread and is only a concern on wind loaded slopes or in areas that tend to get more snowfall than the majority of the Summit Lake forecast zone. We have seen a few examples of avalanches that most likely released on this layer, one small avalanche on Tenderfoot on March 3rd and another large avalanche on LV Ray near Carter Lake on March 11th. 

    The layer of buried surface hoar could cause wind slabs to remain triggerable by a person for much longer than normal. The size of these avalanches is expected to be much smaller than in the other forecast areas due to the lack of widespread snowfall in recent weeks. However, we still want to let folks know that this is a potential issue in Summit Lake.

    To assess the conditions, you can use hand pits or snow pits to check for the weak layer within the upper 1-2' of the snowpack. Typically, if the layer of surface hoar is intact, you will have easy shears in hand pits and unstable results in snowpit tests. Since the layer stayed on the surface for longer in Summit Lake, wind, sun, and ski tracks likely destroyed it in many areas before it was buried. 

    (3/11/2025)

    Cornce fall that triggered a large slab below in the Carter Lake area that is south of Summit Lake. This occurred on Monday, March 11.

  • Deep Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    2–3

    There are several different buried weak layers in the Summit Lake area that we are monitoring. The lack of recent avalanche activity on these deeper weak layers indicates that natural and human triggered avalanches are unlikely. However, they could come back to life if we get a significant snowfall or as the sun starts to melt the snowpack, and wet avalanches become a concern. The most likely place to trigger a buried weak layer is from a shallow spot near rocks on the edge of a start zone with a deeper snowpack.

    Other concerns today include loose snow avalanches on steep slopes triggered by the sun, cornice fall, and glide avalanches.  Try to avoid traveling underneath glide cracks or expose one person at a time to minimize time underneath these unpredictable hazards. 

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