Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Very warm temperatures will continue one more day, and the snowpack is undergoing transition. Glide and cornice avalanches have been releasing, wet loose and wet slab avalanches may be easy to trigger, and the snowpack is often unsupportable and mushy. Avoid going on steep slopes if they are unsupportable, and plan your exit to steer clear of overhead hazards.

Avalanche problems

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    Snow surfaces will quickly become unsupportable as the sun comes out. Don't expect much of a re-freeze. Wet loose avalanches may first become active on east aspects, then quickly move to south and west as the sun rises higher in the sky. Wet slabs could also be triggered, as observed easily triggered on Mt McCausland on Saturday. 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. Wet slides have begun to occur even on north-facing slopes, and wet slides on most aspects could gouge down into deeper layers.

    If you choose to go into the mountains, plan your exit strategy to avoid steep slopes and stay out from underneath overhead dangers.

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

  • Glide Cracks

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

    Keep a keen eye out for glide cracks, moats, 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 without warning. Use extra caution to avoid going on or under slopes with glide cracks and cornices.

    There are seemingly more glide cracks and snow-covered rock slabs than typical, and I would expect more activity in the coming days. The mid-January layer is about 6-8 feet below the surface and meltwater may be close to reaching it on many slopes. This layer could produce very large avalanches at some point this spring.

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

Avalanche Discussion

The snowpack is weak and punchy in most places, and I wouldn't expect much of a refreeze overnight. 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 and Saturday, with addition of some ski triggered wet slabs off the south side of Mount McCausland. Wet slides are beginning to occur on all aspects. Many have been big enough to bury or kill a person. Glide avalanches began occurring on Wednesday, and activity appears to be picking. Multiple D2-D3 glide avalanches were observed on Friday and Saturday (see photo below for a very large glide off Kyes Peak from Friday).

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.  

This is the final full avalanche forecast product of the 2020-21 season. As our capacity thins during the warmer months, please continue to share your observations and make use of our mountain weather forecasts (daily through the end of April). From all the forecasters at NWAC, thank you for all your support that makes this product possible and we look forward to resuming full operations in late 2021.

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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