Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Watch for pockets of wind deposited snow at mid and upper elevations Monday. When you see small drifts or a textured snow surface anticipate wind loading on nearby slopes. Use caution in rocky terrain where these small wind slabs may result in big consequences. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    The new snow and strong southerly winds may combine to form shallow slabs on the lee sides of exposed features. As you ascend in elevation, be on the lookout for clues that the wind transported the snow. Small drifts, fresh cornices, and a textured snow surface can indicate that wind slabs may exist nearby. You’re most likely to trigger one of these shallow deposits near the base of cliffs, on rocky slopes, or in confined areas. Even though these slides should remain small, they can still harm you in higher consequence terrain.

    (3/7/2021) Example: We intentionally triggered this small wind slab on a test slope near treeline. Small features like this can help highlight conditions on larger slopes. NW, 6100'. SS-ASc-D1-R2-S

Avalanche Discussion

This isn’t a particularly impressive storm, but some locations could receive 4-6” of snow at upper elevations by Monday morning. Sites near Mt St Helens and Mt Rainier should see the greatest snowfall totals. This new snow will fall with a strong cooling trend which should limit slab development and avalanche hazard outside of wind-affected areas. As a result in locations that receive less snow and/or less wind, you could encounter locally lower avalanche danger. 

The new snow will accumulate on two very different surfaces depending on aspect. On more southerly slopes. The new snow may struggle to stick to a very firm crust formed during last weeks warm sunny weather. In these locations, slabs may trigger more easily. In shaded terrain, the new snow will fall on a mostly soft surface. Either way, we anticipate any avalanche issues to remain within the new snow. Below thse surficial differences, the upper snowpack remains similar despite aspect. The upper snowpack consist of dry winter-like layers where you can still see recent storms and crusts formed over the past month. 

Areas of the West-South zone may see sun breaks and some clearing on Monday. If that occurs, you could encounter piles of new rollerballs and even a few very small loose wet slides. The minimal new snow should limit the potential for any sizeable loose wet avalanches. However, with 4” over a crust on southerly aspects, some of these small point release slides could run far and fast. 

Given the recent weather, you may encounter variable travel conditions depending on aspect and elevation. You could encounter firm icy slopes, wet punchy snow, breakable crust, and soft powder on Monday. Give yourself extra time to deal with these diverse conditions. 

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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