Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

 A heavy layer of snow, 6-10" deep, fell Friday night,  and in thicker wind-affected locations it is possible for you to trigger an avalanche failing near the bottom of the layer. Your largest areas of concern are below ridgelines or around features, and on steep unsupported slopes. Steer around steep, wind loaded slopes, or any other steep slopes if you notice red flags like long, shooting cracks. 

Avalanche problems

  • Wind Slabs

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

    You could trigger an avalanche in steep, wind-loaded locations on Sunday. A heavy slab sits over softer snow in most areas. This slab structure was found to be stubborn on Saturday, however in wind-loaded locations the slab may be more reactive. Failures could occur at the bottom of the new snow layer, which started as a layer of graupel Friday evening, although this layer usually strengthens quickly. Another layer of concern is a couple inches below the new snow, where a weak layer of facets formed during last weekend's cold snap. Avalanches could fail six inches to a foot deep, or they could fail deeper depending on how much wind loading occurred.

    You can dig down to these potential weak layers to see if they exist and determine whether they are reactive in a relatively shallow pit.  Long, shooting cracks traveling out from your feet or sled, whumphs, and recent avalanches are some of your best indicators to stick to lower-angle terrain. Light snow is expected to fall Saturday night and  Sunday. Wind-textured or firmer surfaces hinting to wind slabs may be hidden by shallow deposits of less wind-affected snow. In addition to disguising old drifts, avalanches could occur in the shallower more recent snow layer as well.  Conditions vary throughout the zone and it's important to make your own decisions based on the clues you have. Avoid wind-loaded slopes greater than 35 degrees for Sunday. 

    Wind slabs like this, or deeper, could fail on steep slopes with a human trigger on Sunday.

    Photo: Irene Henninger

Avalanche Discussion

Lower elevations mainly received rain Friday night, and as you near treeline you'll begin to find a thicker coating of new snow. In general, the lower elevation snowpack is pretty bony right now. Even at higher elevations, varying amounts of snow exist depending on where you are in the West Central zone. If you're near the periphery, take a look at the neighboring zone's forecast. In many locations throughout the Cascades temperatures increased Sunday afternoon and rollerballs and small wet loose avalanches occurred. We aren't expecting as much wet snow activity on Sunday, but be prepared to find signs of it from the day before. 

 

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