Bulletin d’avalanche

Summit Lake

Chugach National Forest Avalanche Center
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Danger d’avalanche

Sat
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Points saillants

 While the day will start out quiet, an atmospheric river is taking aim at southcentral Alaska and expected to begin impacting the Kenai Peninsula as early as this afternoon.  As winds, temperatures and precip rates increase throughout the day and overnight, expect the avalanche danger to rise as well. The snowpack in the Summit Lake area  still sports a myraid of persistent weak layers 2-4' deep above 1,000'.  It'll become increasingly possible for a human to trigger an avalanche on any one of these layers as the storm progresses.   Winds are forecasted to be in the mid-20s, gusting to the 40's from the SSE keeping wind slabs as avalanche problem #2 today.

Today will be a good day to ensure you are out of the field before the weather makes a turn for the worse.

Problèmes avalancheux

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3.5

    With a much thinner snowpack than in Turnagain Pass, the weight of a skier or rider is more likely to impact any number of weak layers in the Summit Lake area.  This scenario will be more likely in the alpine or rocky outcrops where the slab thins out.  Persistent slab avalanche problems are inherintly tricky to manage and require strict travel protocol to minimize risk.  This includes setting conservative skin tracks, exposing one person at a time to avalanche terrain and clearing well out of runout zones at the bottom of a slope.  

    While certainly possible for a skier to trigger an avalanche on one of these layers today, we'll be watching intently to see if these deep persistent weak layers are re-activated with this weekend's warm, wet and windy weather.  

    Wet loose: With temps climbing and an atmospheric river forming, we may see some wet loose avalanches late in the day.  These are likely to take the shape of small point releases or rollerballs on very steep, mid-elevation slopes.  If they pick up enough mass or gouge deep enough, we could see these initiate a more dangerous slab avalanche.  If you're skiing or riding on dry surface snow in the morning and that dry snow begins to see rain, it'll be time to retreat off of steep slopes.  The rain/ snow line may reach as high as 2,000' today in the Summit Lake area before (unfortunately) climbing even higher on Saturday.

    (1/20/2025)

    Snowpack structure from a pit on Tenderfoot earlier in the week, 3,200'.  Tests showed unstable results with weak snow near the ground failing with moderate force.

    Photo: Daniel Krueger

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    SSE winds are forecasted to impact the Summit zone today ahead of the atmospheric river.  Be on the lookout for fresh wind slabs forming in the upper elevations today.  Shooting cracks or a change in surface conditions to a stiffer or hollow feeling snowpack are indications you've found a wind slab.  Wind slabs are likely to be on the smaller side but can quickly spell trouble if triggered above a terrain trap (gullies, trees, cliffs, rocks, etc.).  

    Cornice: Cornices continue to grow with the steady march of storms and may be sensitive to the weight of a person or machine.   Anticipate cornices to break further back than expected and give corniced ridges a wide margin.

    (1/22/2025)

    Signs of wind loading from the sunlit cornice on Butch Mtn. 

    Photo: Daniel Krueger

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