Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

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

Chilly East winds should continue Saturday night into Sunday, keeping Wind Slab formation as the most likely avalanche hazard problem you'll encounter. Look for actively blowing snow or areas that look “fat” compared to the surrounding terrain to help you identify where these unstable pockets of snow may be lurking. At lower elevations, you will still need to manage early-season hazards as you travel.

Avalanche problems

  • Wind Slabs

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

    In addition to the Wind Slabs formed on Friday night and Saturday, you could find that some fresh slabs have developed by Sunday morning due to continued East winds at the Pass. Specific terrain features such as convex rollovers, the base of cliffs, or the sides of rock gullies will be the most likely location for these unstable pockets of snow to form. Of course, they are also prone to develop on the leeward side of ridgelines. These slabs could exist on aspects where you’re not used to seeing them, so keep a keen eye. Your number one indicator of Wind Slab formation should continue to be actively blowing snow. You can also look for fresh cornices and drifts, or large pillow-like piles of snow to help you identify areas to avoid. If you are traveling in snow that is firm or has a textured surface, you are likely already in wind-affected terrain.

    (12/3/2022)

    Actively blowing snow, freshly building sharp cornices, and textured surfaces. All easy to identify signs of wind-loading. Look for slabs to develop on the slopes on the left side of the picture.

    Photo: Dallas Glass

Avalanche Discussion

Saturday was a beautiful day up on the pass with mostly clear skies accompanying cool temperatures and winds. Some low-level clouds due to the east flow crept in and out of the valley floors, but at upper elevations, the sun was out and the views were spectacular. 

NWAC forecasters took advantage of the nice weather by traveling to the top of Alpental with help from the Alpental Pro Patrol. They found plenty of evidence of wind effect with actively blowing snow, textured surfaces, fresh cornices, and some sensitive fresh Wind Slabs on convex test slopes. Digging in the snow, our suspicions of a generally strong lower snowpack were confirmed, at least in this location. While some older weak snow was found below a crust, it was unreactive in snowpack tests and was uninspiring when looked at in magnification. The main topic of conversation for our descent was the recent snow and wind and how to manage freshly built slabs. 

At lower elevations, shrubs, boulders, and holes are more prevalent and provided another hazard to manage. Expect similar conditions to exist until we receive more snow to thicken our early-season snowpack.

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