Lawinenlagebericht

Stevens Pass

Northwest Avalanche Center
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Lawinengefahr

Sun
Hochgebirge
3 · Erheblich
Waldgrenze
3 · Erheblich
Unterhalb
3 · Erheblich
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Kernpunkte

The warmest temperatures so far this season are causing the mountains to shed. Glide avalanches have been releasing, wet loose avalanches may be very easy to trigger, cornices are sagging, and the snowpack is generally unsupportable and mushy. Avoid going on steep slopes if they are unsupportable, or if you see cornices or glide cracks above. 

Lawinenprobleme

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    2

    Snow surfaces are quickly becoming unsupportable. Don't expect a re-freeze. Wet loose avalanches will first become active on east aspects, then quickly move to south and west as the sun rises higher in the sky. Take note of what the snow surfaces are like. Do you punch through easily, or stay on top? If the snow is unsupportable and punchy, it is probably weak enough to entrain an avalanche. These slides have begun to occur even on north-facing slopes, and slides on most aspects could gouge down into deeper layers. It will be safest to avoid going onto, or underneath steep slopes as this 'shed cycle' ensues. 

    If you choose to go into the mountains this weekend, plan your exit strategy with overhead dangers in mind, and avoid complex terrain.

    (4/16/2021) Many overlapping wet loose avalanches from an east-facing slope near Stevens Pass.

  • Glide Cracks

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Possible
    Größe
    2–3

    Look out for glide cracks, or crevasse-like cracks on steep slopes. These may release spontaneously, creating very large and destructive avalanches. Similarly, cornices loom over some ridgelines, have been dripping, and may fail with the hot temperatures. Use extra caution to avoid being on or under slopes with glide cracks and cornices.

    Water has begun to run through the lower elevation snowpack and many glide avalanches have been releasing. With both of these red flags in mind, along with continued soaring temperatures, more glide avalanches are expected to release. This season there are seemingly more glide cracks and snow-covered rock slabs than is typical, so we expect more may occur in the coming days. The mid-January layer is about 6-8 feet below the surface and has yet to see melt-water on most slopes. This layer could produce very large avalanches as warming temperatures continue.

    (4/16/2021) A wide glide crack, along with wet loose avalanches.

Avalanche Discussion

Each day continues to be warmer than the last, and the warmest day so far this winter is on tap for Saturday. The snowpack is weak and punchy in most places, and we're getting to the point where trying to catch a 'corn window' may be useless. With the hot temperatures, meltwater is beginning to filter deeper into the snowpack. This is quickly changing our snowpack from a dry winter-like pack to a wet and mushy one. Observers continued to report numerous wet loose avalanches on Friday. These are beginning to gouge deeper into the snowpack, and are beginning to occur on all aspects. Many of these were big enough to bury or kill a person. Large glide avalanches began occurring on Wednesday, and activity appears to be increasing throughout the Cascades. Multiple D2-D3 glide avalanches were observed on Friday (see photo below for a very large glide off Kyes Peak).

Most northerly aspects are now warming up, and may hold breakable crust or wet snow on the surfaces. On east through south through west aspects, the upper snowpack consists of mostly melt forms in various states of being melted, and is losing strength quickly with the rapid warming trend. The last set of storms brought a total of 1.5-3 feet of snow in two different storms on the 7th and 9th.  

Daily avalanche forecasts will end on Sunday, April 18th.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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