Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 3 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You can trigger avalanches in wind-drifted deposits which formed in the snow we received in the last 2 days. Look for signs of slab development such as active wind transport, thicker pillows of snow, and clues like shooting cracks breaking from your steps. Stay off steep slopes in areas where you identify signs of weakness or thicker pillows of snow, especially as you gain elevation, where wind-effect will be greater. 

Avalanche problems

  • Wind Slabs

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

    Conditions are expected to change quickly the higher up you go, and likelihood of triggering a slab avalanche will increase. Look for signs of active wind transport and drifting snow, such as blowing snow and fresh cornice development. Identify surface textures like wind etching and rippling to help decipher areas that may act as a cohesive slab. Check for shooting cracks and use small test slopes to see how wind-drifted snow may react before going onto steep terrain.

    Slabs may react differently depending on the slope - most slopes will have a frozen crust beneath the new snow, but shaded north-facing terrain could hold dry, weak snow underneath. Snow could break on those layers, at the interface, or it could fail on a new wind slab within the new snow layer. We expect avalanches to be less than a foot deep, and most will be small, but they will likely grow in size as you travel higher. If you do find signs of instability, or identify wind-loaded surfaces, steer around slopes greater than 35°, especially in areas where terrain traps are present.

    You may be able to trigger small dry loose snow avalanches in non wind-affected areas on steep slopes. If the sun pokes out, which is most likely during the morning, small wet loose avalanches could occur as well. 

     

    (3/22/2021) This is an old photo of conditions similar to what you might encounter on Saturday. D1 slab avalanche near Tye Peak, skier triggered from the ridge. It was about 60ft wide and 6-8" deep, running on the storm snow interface. Photo: Irene Henninger

Avalanche Discussion

Weather forecasts for Friday night are calling for just under 6 inches of snow, but we're also possibly set up in a convergence zone so numbers vary widely regarding what we'll end up with for precipitation amounts. If we get more or less snow than forecasted, the avalanche forecast may be less accurate so be sure to evaluate conditions as you travel. 

In the past week, we had an initial spring thaw, along with a prolonged cycle of wet loose avalanches and glide activity. Expect to find frozen debris in many areas hidden under the new snow. Avoid slopes with glide cracks, as glide avalanches have been known to release a few days after temperatures have cooled, sometimes resulting in deadly outcomes. Another spring concern is very large cornice, another feature it would be wise to give a very large berth to, both from above and below. 

 

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