Avalanche forecast

Summit Lake

Chugach National Forest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

The weather has quieted down for now, but there are still chances a person could trigger a very large avalanche 2 to 4' deep in Summit Lake above 1,000'. Southwest ridgetop winds are forecast to increase today which could create some fresh wind slabs 6" to 1' deep in the upper elevations. These should be fairly small, but could trigger one of the larger avalanches mentioned above. The only way to completely avoid triggering one of these large slides is to stick to lower angle slopes.

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2.5–3.5

    Managing the deep persistent slab problem is extremely challenging. While the chances of triggering an avalanche goes down with quiet weather, the consequences of releasing one of these beasts would be devestating. Avoid thinner areas of the snowpack such as rocky outcroppings or the margins of uniform slopes. The slab may be thinner in these areas, making it easier for the weight of a human to impact the weak layer. If you are getting out onto steeper slopes safe travel protocols are essential. Travel one at a time, watch your partners and stop in places well out of the way of the runout.

    On Monday one of our forecasters and his partner were traveling on the ridge of Tenderfoot and felt a collapse (whumpf). They dug a snowpit close by and got unstable results, see photo to the right. A lot of times this type of avalanche problem will not give any feedback so it is helpful that the snowpack gave us some information. A whumpf is a serious red flag that means an avalanche could have occurred if the slope was steep enough. 

    (1/20/2025)

    Snowpit near the collapse (whumpf) that Daniel heard/felt at 3,200' on Tenderfoot on Monday. The tests showed unstable results with weak snow near the ground failing with moderate force.

    Photo: Daniel Krueger

  • Wind Slabs

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

    Southwest ridgetop winds are fairly light as of early this morning, but are forecast to pick up to 20 to 25 mph today. If this happens, fresh wind slabs will be forming that should be on the small side. The scary thing about the wind slabs today is that a wind slab could trigger the larger and more dangerous deep persistent slab avalanche. Watch for blowing snow on the ridgelines and feel for firm snow over softer snow to know you have found a wind slab. A shooting crack means the slope is prime to avalanche.

    Cornice: Cornices may not fail naturally today, but they have grown large after all of these storms and strong winds. Give them some space on the ridgelines as they could still be sensitive to the weight of a person or machine and they break back further than we expect.

    Dry Loose Avalanches: Dry loose avalanches continue to be observed in our forecast areas. These should be fairly small, but watch for consequences below like rocks or cliffs in case we get caught up in "sluff" by surprise.

    (1/20/2025)

    Shooting cracks underfoot in Turnagain Pass on Monday.

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