Avalanche forecast

Stevens Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Progressively warmer temperatures and strong sun will maintain a threat of wet avalanches on slopes steeper than 35 degrees. Time your travel to be off of and out from under sun-exposed slopes before the snow becomes wet and weak. Steer around wind features and drifts just below ridges at upper elevations.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1

    While wind slab avalanches are unlikely, watch for fresh slabs that may have formed from east winds since Monday night.  The best chance for triggering an avalanche is on leeward sides of ridges above treeline. Steer around loaded, leeward slopes and unsupported and wind-sculpted features. Other indicators of wind slab conditions are textured surfaces and firmer or supportive dry snow. East winds will continue, and may still drift snow, through Wednesday.

    (4/10/2021) A small wind slab avalanche triggered on an inconsequential test slope. This was on a leeward, 40 degree slope at ridgetop. Lanham creek, E, 5,450ft.

  • Loose Wet

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

    Wet avalanches will first be active on the east aspects and later on the west aspects. As you move through the mountains, take note of how much the surface snow has frozen or melted.  You may find that conditions change dramatically from one slope to the next and as the day progresses. Plan ahead and give yourself options for travel that include a variety of aspects and elevations. Be ready to move to slopes that are shaded, more frozen, or under 35 degrees. Move off of steep slopes before the snow is unsupportive and weak enough to entrain an avalanche.

    Wednesday will be the warmest day of the week so far. There's still enough dry snow available to produce avalanches especially at mid to upper elevations and on northeast and northwest aspects. East wind may again keep surfaces a bit cooler than normal, especially at mid to upper elevations. 

    (4/11/2021) Natural wet avalanches ran in very steep, east-facing terrain. Stevens Pass zone

Avalanche Discussion

Glide cracks have again begun to open in steep rocky terrain. Cornices loom over some ridgelines and may fall during the warm days this week. Use extra caution to avoid being on or under features with glide cracks and cornices. We expect significantly warmer temperatures starting on Thursday. Dangerous wet avalanche conditions may develop by the weekend.

On Sunday through Tuesday, observers reported numerous wet loose avalanches on sun-exposed slopes with some on northwest and northeast aspects. A few of these were big enough to bury or kill a person. On Tuesday in upper Nason Creek, I found surface conditions varied significantly by aspect and elevation. All but the most shaded slopes above 5,000ft are capped with crusts. The top two feet of the snowpack varied from mostly dry recent snow to all melt forms (from very hard to soft and weak) and everything in between. Moderate blowing snow was reported above treeline. On Saturday, northerly aspects in the Lanham Creek drainage held mostly dry, winter-like layers with a handful of thin crusts in the top 5 feet of the snowpack. 

The last two days brought gradually clearing skies and warming temperatures. A storm on April 9-10th delivered 20-40cm of very cold snow with strong northwest winds. An earlier storm on the 7-8th brought 20-60cm of snow. This was also followed by a brief warm-up and wet avalanche cycle late last week. Many northerly slopes hold a mostly dry snowpack in the top 5 feet. The upper snowpack on east through south through west aspects consists of mostly melt forms in various states of being melted or frozen. The mid-January layer is about 6-8 feet below the surface and has yet to see melt-water on most slopes. This layer could potentially produce avalanches with future warming events.

Daily avalanche forecasts will end on Sunday, April 18th.

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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