Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Pay attention to changing conditions when the sun comes out Monday. Solar radiation may cause loose snow avalanches on steep sun-exposed slopes. Triggering large avalanches in wind drifted snow still remains a concern, primarily on convex features steeper than 35 degrees near and above treeline. Use visual clues to identify and avoid wind loaded slopes, and seek out lower-angled and wind-sheltered terrain to reduce your risk.

Avalanche problems

  • Loose Wet

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

    Keep a close eye on steep sun-exposed slopes where solar radiation may be strong enough to destabilize snow surfaces and create small loose avalanches. Watch for rollerballs and pinwheels as evidence snow surfaces are becoming wet and weak. Snow shedding from trees and rocks may initiate loose avalanches in steep terrain below. Minimize your exposure to slopes greater than 35 degrees in direct sunlight and move to shaded terrain to avoid the problem. Loose snow sluffs could even trigger slab avalanches as they run downslope.

    Example photo of a small, skier trigged loose snow avalanche running on a crust

  • Wind Slabs

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

    Recently formed slabs of wind drifted snow will continue to be reactive in the right location with a human trigger. Cohesive slabs rest over the most recent (12/21) melt-freeze crust, which may act as a good sliding surface for avalanches. Look for shooting cracks and strong over weak layering as you assess areas of wind drifted snow. Use test slopes to check how well recent slabs are bonding before venturing into bigger terrain. Avoid wind loaded slopes greater than 35 degrees if you find signs of instability or fresh avalanches. Slabs will be deeper and wider in higher elevation terrain and near ridgelines. When in doubt, seek out wind-sheltered slopes and terrain less than 35 degrees.  

    Example windslab running on a crust.

Avalanche Discussion

About 6-8in of new snow accumulated in the Stevens Pass zone since Christmas. Southwest winds were strong, and observers reported intense wind transport in exposed locations over the weekend. There is uncertainty about how the new snow is bonding to existing surfaces in upper elevation, alpine terrain.  Previous snow surfaces consisted of this slick crust, surface hoar, near-surface facets, and wind broken particles. In windward locations, the recent crust could still make for some slick and challenging travel. 

The last deep persistent slabs occurred over a week ago, and recent observations in the area indicate this layer is now unreactive to triggers. In isolated areas, you may still find weak snow deeper in the snowpack, but very large and destructive avalanches on this layer are unlikely. Additionally, the stout crust formed on 12/21 appears to be stabilizing the lower snowpack, and the weak layers associated with the widespread natural avalanche cycle last week are moist and gaining strength. 

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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