Avalanche forecast

Summit Lake

Chugach National Forest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
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Highlights

Heavy snow and rain with strong easterly winds will continue today. This will make for dangerous avalanche conditions with wet snow avalanche problems below 2500', and new snow avalanche problems including storm and wind slabs at higher elevations. This is adding stress to weak layers buried deeper in the snowpack, which may make bigger avalanches. With all of the activity we are expecting, it will be important to travel cautiously and avoid steep terrain.

Avalanche problems

  • Wind Slabs

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

    If you manage to get above the rain into new snow, it is very likely you will find dangerous conditions within the new and windblown snow from the past two days. These are becoming larger and more sensitive as the storm continues, and although there has been less precipitation in the Summit Lake zone than in other areas, they will still be large enough to be dangerous today. Be on the lookout for natural avalanches as well as an increasing likelihood that a person will be able to trigger an avalanche through the day. Keep in mind, a relatively small avalanche failing within new and windblown snow may be able to trigger a larger avalanche failing deeper in the snowpack. More on this in Problem 2 below.

    It has been a soggy few days since precipitation started Thursday afternoon. Here are the totals from Thursday through Sunday morning with estimated snowfall amounts above 2500'. The majority of this fell within the past 24 hours:

    • Girdwood: 2.3" water (6-10" snow)
    • Portage: 8.0" water (24-30" snow)
    • Turnagain Pass: 3.0" water (18-24" snow)
    • Summit Lake: 0.7" water (6-8" snow)
    • Seward/Lost Lake: 2.3" water (18-24" snow) 

    (12/22/2024)

    Predicted precipitation totals, Sunday morning through Monday morning.

    Graphic: NWS Anchorage

  • Persistent Slabs

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

    The weak layers buried in the middle and bottom of the Summit Lake snowpack are experiencing the first loading event in about two weeks. Although precipitation totals are going to be somewhat modest, this will be adding stress to these deeper layers. This will increase the likelihood of triggering a larger avalanche, and there is a possibility that could happen all the way down at the ground. If the storm and wind slabs discussed in Problem 1 don't give you enough reason to travel cautiously today, this setup should. This problem seems to be more likely at higher elevations, and it can be avoided by staying away from steep upper elevation start zones.

    (12/19/2024)

    Multiple weak layers will be getting tested as the snow and wind continues today.

    Photo: Daniel Krueger

  • Loose Wet

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

    Rain has been falling for two days now, and it is increasing the size and likelihood of wet snow avalanches. These can release naturally, and they may also be triggered by a person. If you decide to venture into the backcountry terrain, give steep slopes a wide berth and be aware of the possibility of avalanches releasing in steep overhead terrain. This will most likely involve just a few inches of heavy, saturated snow near the surface. However, that may still be a legitimate concern if an avalanche were to carry you through trees, rocks, or into a creek or gulley.

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