Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Watch how the snow surface is changing throughout the day due to warming temperatures. If you’re standing in new dry snow or wet unconsolidated snow, it’s time to start thinking about avalanches.

Avalanche problems

  • Wind Slabs

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

    Thursday’s storm was windy and although most areas saw rain, snow did fall at higher elevations. If you ascend in elevation and find that you have transitioned to dry snow, start to think about Wind Slab avalanches. Wind Slabs often form on convex features, near the base of cliffs, the sides of gullies, or on the leeward side of ridgelines. You can use visual clues such as textured surfaces, freshly built cornices, or actively blowing snow to help you determine if these features are wind-loaded and you should avoid them. 

    (1/15/2022)

    If you're above the rain/snow line, like on a volcano, you could find avalanches like this skier-triggered Wind Slab on Mount St. Helens last week.

    HS-AS-R2-D2

    Photo: Jeff Zimmerman

  • Loose Wet

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

    Look for wet avalanche danger to increase as temperatures warm and the snow surface destabilizes on Friday. Dry snow will be more susceptible to warming and therefore more likely to produce Wet Loose avalanches. Areas that contain a frozen surface will take longer to break down. Once they do, avalanches could be more stubborn to trigger in these areas. Much of the zone has seen multiple rounds of wet avalanches in the last week, but that doesn’t mean that every area has reached its tipping point or can’t produce another avalanche. Look for wet unconsolidated surfaces as an indication that Wet Loose avalanches are possible on steep features over 35 degrees.

    (1/16/2022)

    Wet loose avalanches on an east aspect near 6800ft on Hogback Mountain. Look for similar avalanches once temperatures start to warm on Friday.

    Photo: Public Observation

Avalanche Discussion

Thursday’s storm delivered around 0.5” of water to the crest, over 1” to Mount St. Helens, and a whopping 2.35” of water to Paradise. In almost all locations, rain was the dominant precipitation type. At upper elevations on the volcanoes or the tops of the highest peaks near the crest, snow was able to fall with gusty winds. Thursday afternoon, temperatures started to cool as precipitation tapered. This trend should continue into Friday morning, helping snow surfaces to freeze from the top down. The cool weather should be short lived, however. By Friday afternoon, we expect freezing levels approaching 8000 feet as we head toward a warm and sunny weekend. This warm-up should reinvigorate our concern for wet avalanches by breaking down the snow surface or destabilizing the high elevation new snow. If fresh cornices were built at upper elevations, look for them to sag or fail. Wind Slabs that may be reactive in the morning could transition toward wet slabs in the afternoon. Generally speaking, the snowpack has been through multiple rounds of springlike weather over the past week and should be well suited to handle most of what this cycle has to offer, but wet avalanches are unpredictable and can surprise even seasoned veterans of the avalanche world.

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