Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Stormy weather with very strong winds Monday could make it difficult to see and avoid wind loaded features. Expect the avalanche hazard to increase through the day as snow totals increase and the wind piles snow into deeper slabs. Sticking to sheltered and more treed slopes away from the effects of the wind may help you navigate and avoid the avalanche hazard.

Avalanche problems

  • Wind Slabs

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

    This storm doesn’t look like a big snow producer for the Pass, but modest snow totals combined with strong winds could produce avalanches especially later in the day and at upper elevations. Anytime you transition out of the trees and into the open, windblown snow should be on your mind. You may see signs of wind slabs such as blowing snow, wind drifts, and fresh cornices well below ridgeline, near exposed terrain features, and along the sides of mid-slope gullies. Steer away from wind affected areas greater than 35 degrees. Remember poor visibility can make it difficult to identify and avoid many of these wind-loaded slopes.

    (11/26/2020) Example: Cross loaded slopes near Mt Rainier: The textured snow surface in this photo demonstrates cross-loading along the sides of gullies. Cross-loading can be difficult to manage as you travel up and down terrain.

Avalanche Discussion

The new snow on Monday will accumulate on a variety of snow surfaces and this may affect how well it bonds. On more southerly aspects a firm sun crust formed the past several days and could act as the bed surface for any resulting avalanches. In shadier locations, thin surface crusts, settled powder, and possibly surface hoar may be found at this interface. Surface hoar survived Sunday in nearby areas like the Teanaway River (East-Central),  Cyrstal Mountain, and White Pass (West-South). While it's not likely widespread, you're most likely to encounter buried surface hoar on shaded and sheltered slopes and in the eastern portions of the forecast area. As you travel you may find that the new snow reacts differently as you change locations making it more difficult to predict and manage. 

The height of snow varies greatly by elevation around Snoqualmie Pass. At lower elevations, and in spots further east, a thin early season snowpack (24-30”/ 60-80cm) exist. Expect numerous obstacles including open creeks, logs, and rocks. Above 4000’ the snowpack begins to increase dramatically (60-75”/ 150-190cm) and coverage becomes more consistent. While several crusts reside in the snowpack, most avalanche activity is expected to occur on this new interface (11/30).

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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