Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Winds should continue to move snow into potentially unstable piles on Sunday. If you see snow actively being blown onto a slope, the best thing to do is avoid that feature. Choose travel routes that leave you with options to avoid wind-prone areas in case you see signs of instability.

Avalanche problems

  • Wind Slabs

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

    Continued East winds could thicken existing or create new Wind Slabs around the West South zone on Sunday. These slabs could exist on aspects where you’re not used to seeing them, so keep a keen eye. 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. 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. In addition to the more obvious leeward side of ridgelines, these slabs often like to form in confined rocky gullies, on convex rollovers, or at the base of cliffs. 

    (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

It was a beautiful but blustery day throughout much of the West South zone on Saturday. Observations of actively blowing snow were received from backcountry skiers in the Crystal Mountain area. Across the street, skiers at Paradise had a similar story. Both groups mentioned the beautiful weather, cool and gusty winds affecting the snow in open wind-prone areas, and cold low-density snow in sheltered areas. NWAC weather stations and webcam imagery suggest similar conditions were found near White Pass and as far down as Mount St. Helens. 

Crystal Mountain Pro Patrol was the only group to report new avalanches on Saturday, with 4-6” Wind Slabs triggered during their morning mitigation work. Some of these slabs were found mid-slope on cross-loaded gullies and all were confined to this week’s new snow. However, on Thursday, Crystal Patrol triggered 3 larger slides that broke into deeper layers in the snowpack (likely the 11/22 interface). These slides all occurred in upper elevation, wind-loaded terrain with a northerly aspect and remind us that early-season snowpacks are notoriously variable. 

Speaking of early-season snowpacks, at lower elevations you will likely still need to manage shrubs, boulders, and open holes as you travel. You should expect these hazards to persist until we receive more snow..

Regions covered