Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

Backcountry travelers can still trigger avalanches in areas of wind drifted snow. Identify and avoid steep terrain where you find denser slabs sitting on softer snow below.  Anticipate danger from loose wet avalanches on southerly slopes if skies are clearer expected.

Avalanche problems

  • Wind Slabs

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

    You can still trigger a wind slab in upper elevation terrain on Tuesday. New snow amounts from the last storm vary across the zone. The depth of recent wind slabs will be dependent on the amount of snow available for transport by strong alpine winds over the past 24 hours. Wind slabs should be identifiable as dense looking pillow or lens shaped drifts or may sound hollow when you travel across them. Track the distribution of wind loading and scouring as you gain elevation to identify slopes where you may find wind slab. You are more likely to trigger one on steep convex rolls or other trigger points.  Use simple tests to see how well they are bonded to layers below - or simply bypass steep wind loaded features by using lower angle, planar terrain.

    (2/6/2022)

    Snowmobile triggered wind slab avalanche at Schriebers/Mt. Baker. South east aspect at 6200'. Note cornices directly above crown indicating wind loading on the slope.

    Photo: Graham Clark

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Observations in West Central confirmed the presence of sugary, weak facets between melt freeze crusts about 1’ below the snow surface. Avalanche activity in West North at these layers was sparse but consistent in the last week. Around Stevens Pass there were no reported avalanches despite plenty of traffic in suspect areas. There is an increasingly low chance you could trigger one of these avalanches but the weak snowpack structure still indicates they are worth factoring into your plan. These avalanches have occurred where there are 2 or more feet of new snow over the crust. You can track the depth of new snow over the crust by pushing the handle of a ski pole into the new snow until it stops at the upper crust layer.

    Don't ignore obvious signs of instability like whumphing, shooting cracks, or previous avalanche activity where you identify old crusts in the bed surface. Minimize travel on steep slopes at upper elevations and remember persistent slab avalanches can be triggered from low on the slope or remotely. When assessing terrain, factor in not only the possibility of triggering a large avalanche but also the consequences in the terrain below if you are caught. 

Avalanche Discussion

Observers in the Mountain Loop found wet snow up to 4500' with a supportable crust from that elevation to treeline. No wet avalanche activity was observed but is possible on Tuesday, especially in the southern portion of West Central that is could receive more sun and warming than areas near Highway 20. A very intact crust-facet sandwich was found in the same area at 5000' on a north facing slope.  Snowpack testing produced positive results with ECTP's and a PST 40/100 (end). 

No new avalanche activity was reported on Monday. High pressure, sunny skies, and much higher freezing levels are expected in the second half of the week. A corresponding increase in danger from wet avalanches is anticipated as well. 

 

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