Bollettino valanghe

Summit Lake

Chugach National Forest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto last year. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Lingering wind slabs and the potential for new wind slabs around 1’ will be the biggest concern in upper elevations on wind loaded slopes. In some places a buried weak layer around 1 to 2’ deep could cause a large avalanche. To avoid this problem stick to lower angle slopes away from steep overhead terrain.

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SPECIAL ANNOUNCEMENTS:

TODAY is your lucky day! Come find us at the Seattle Ridge motorized parking lot for our annual Turnagain Pass Avalanche Awareness Day! We will be there with Alaska Mining and Diving Supply and the Alaska Avalanche School to chat about avalanches and current conditions and to hang out with the good people of the southcentral Alaska winter community. AMDS will have demo snowmachines, and we’ll be holding down the grill and the fire pit. Stop by anytime from noon until 4:00 p.m. Details Here.

Problemi valanghivi

  • Wind Slabs

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

    Moderate winds from the east may actively blow snow into fresh wind slabs around 1’ deep. These will be more likely at upper elevations, below ridges, rollovers and in cross loaded gullies. Look out for blowing snow which is an indicator fresh wind slabs are forming. Clues like shooting cracks or snow that becomes stiff underneath you mean you are likely traveling on a wind slab. 

    If the sun has a chance to shine and temperatures feel warm it may be easier to trigger a surface snow avalanche on steep solar aspects. These may release from a point and get larger as they carry more snow down the slope or trigger a small slab avalanche. Seek shadier slopes if you find yourself in the sun and see rollerballs releasing. Worst case scenario, one of these avalanches trigger a larger avalanche on a buried weak layer. 

    Other concerns to keep in mind: Limit time spent under cornices and give them a lot of room on ridges. Minimize time spent under glide cracks and avoid them if possible because the can release into a large glide avalanche.

    (3/20/2025)

    Strong easterly wind blowing snow off Butch Mountain.

    Photo: Mik Dalpes

  • Persistent Slabs

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

    The same layer of surface hoar responsible for many human triggered avalanches in Turnagain Pass also exists about 1’ deep or deeper in Summit Lake. We heard a report yesterday of whumpfing/collapses and 30’  shooting cracks on Raven Ridge at an elevation of 2250'. Upon further investigation the party found the buried surface hoar upright about 1’ deep in the snow that easily failed in a test pit (ECTP4). This slope would have triggered an avalanche if it was steep enough. This is one of the few places we have heard of this weak layer presenting concerning clues (Colorado Mtn is the other location). The point is the problem does exist and could trigger an avalanche deep enough to bury a person.

    What we know is that this layer may give stable results in snow tests or be impossible to find on a slope and still trigger an avalanche. This problem may be more likely in zones that have not been explored yet or sheltered from the wind. If you are getting out, especially in a new zone and on steep slopes, be extra cautious. The safest option is to choose lower angle slopes. 

    (3/21/2025)

    Shooting cracks and collapsing/whumpfing snow on Raven's Ridge.

    Photo: Daniel Krueger

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