Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Sun
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Out of date — this forecast expired 4 years ago.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

Another round of wind and snow should renew our concern for small avalanches in wind-drifted terrain on Saturday. Look for these unstable pockets near ridgelines or in confined gullies as you ascend in elevation. Locations that receive the brunt of this storm such as the volcanoes could see more avalanche activity than areas closer to the crest.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Keep an eye out for wind-loaded features near ridgelines, rocky outcrops, confined gullies, or on convex slopes where you’re more likely to trigger an avalanche on Saturday. Shifting wind directions could result in Wind Slabs developing on different aspects than what you may be used to. Look for them on reverse aspects or cross-loaded mid-slope features by using visual clues such as identifying smooth pillow-like piles of snow or areas that look “fat”. Actively blowing snow, fresh cornices, or drifts behind objects can help you identify potential Wind Slab locations. If you suspect a feature to be wind-loaded, best to just steer around it at this time.

    (1/20/2023)

    Example: A  Wind Slab avalanche that was observed on Mt. Adams on 1/20. Note its location below a ridgeline and originating at the base of rocks.

    Photo: Paris Gore

Avalanche Discussion

Thursday night’s storm totals varied across the zone, with the volcanoes being favored and picking up considerably more precipitation than areas closer to the crest. That said, all NWAC weather stations recorded periods of strong winds. Look for this trend to continue on Saturday as another storm pulse impacts the zone, bringing cooling temperatures, snow, and windy conditions. Later in the day as precipitation peters out, the winds should increase and change direction. 

On Friday, NWAC forecasters in the Crystal Mountain area found minimal new snow had fallen on mostly firm surfaces. The depth of new snow varied by elevation and exposure to wind, with some areas being stripped down to the crust. Where it exists, this firm and potentially icy crust could make a good bed surface for this next round of potential avalanches or create difficult travel conditions. Be sure not to slip and take an uncontrolled fall in consequential terrain. 

Prior to Friday's storm, the upper snowpack consisted of 1.5-2.5 ft (45-75cm) of settled snow over the very prominent and stout MLK crust. While you can still find older layers (1/21 and 1/18 interfaces), we’re mainly concerned with avalanches failing at or near the base of the recent snow (1/26).

Regions covered