Avalanche forecast

West Slopes South

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Out of date — this forecast expired 6 years ago.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

Expect the avalanche danger to increase throughout the day Monday as snow accumulates and the wind forms thicker and easier to trigger slabs. You’ll need to identify and avoid features where the wind piles the snow into deeper drifts. Since the stormy weather could make seeing and avoiding these hazardous spots much more difficult, stick to treed and sheltered areas to stay clear of the hazard. 

Avalanche problems

  • Wind Slabs

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

    The forecasted very strong winds dominate the headlines of this weather system and we expect them to create some tricky wind loading conditions especially late in the day and at upper elevations. When very strong and extreme winds transport the snow, they often create erratic wind loading patterns, form slabs well below ridgeline, and can cross-load the sides of mid-slope gullies. Any time you step out of the trees into the open, wind drifted snow should be on your mind. Look for blowing snow, drifts behind objects, and fresh cornices to help your locate and avoid wind loaded features. Remember, when stormy weather limits your visibility it can be hard to avoid what you can’t see.

    (11/26/2020) 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

Monday’s snow will accumulate on a variety of snow surfaces, which may make it difficult to predict and manage. At lower elevations surface hoar was reported on Sunday afternoon near both White Pass and Crystal Mountain. While the sun and wind may have destroyed these weak feathery crystals in many locations, they may have survived on more shaded sheltered areas. On sunnier slopes, a firm crust developed over the last several days. In both of these cases, avalanche activity could fail on this new interface (11/30) and allow avalanches to run far and fast. 

Overall the snowpack around the West-South zone is impressive for the end of November. Sure it’s early season, but generally, you’ll find 40-60” (110-150cm) of snow near treeline. While most early-season obstacles are covered, you may still encounter open creeks and ponds that require additional navigation to avoid. 

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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