Avalanche forecast

West Slopes North

Northwest Avalanche Center
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Avalanche danger

Tue
Alpine
3 · Considerable
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Out of date — this forecast expired 5 years ago.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

We’ve received 4 feet of light fluffy snow in the last 5 days. On steep terrain you could trigger shallow avalanches on the steep slope around you. If you find areas of firmer, wind-affected snow, avoid them on steep slopes.

Avalanche problems

  • Wind Slabs

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

    Wind slab avalanche observations died down in the last day as the winds decreased. You may still find an odd shallow reactive slab, but most recent ones remained less than 6 inches deep. There is more uncertainty at upper elevations, where fewer people traveled in recent days. As you gain elevation, you may encounter thicker ones. 

    The previous light winds and low-density snow made identifying these slabs difficult, and they could also have a coating of non wind-affected snow on top of them. They usually form under cornices or drift around features, such as on lee sides of ridges, near the bases of cliffs, and on gully sides. Travel out on smaller slopes to test them before you move to larger ones. Pay attention to obvious clues such as cracking and slightly thicker feeling snow. If you find wind slabs, avoid them on slopes steeper than 35 degrees.

    A wind feature cracking as a person moves closer. This could mean that the snowpack is unstable. Photo: Pete Durr 

  • Storm Slabs

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

    4 feet of low density snow in 5 days is a lot. Even on non wind-loaded slopes you could encounter soft storm slabs. They may propagate out for a distance, or possibly act more like a dry loose avalanche, simply picking up snow and running in the surface layers. Likelihood of encountering a natural one of these is reducing now that snowfall abated. It is possible that you can trigger one if you’re on a steep slope. 

    Start your day with smaller slopes to determine whether your impact will cause any avalanches. If you’re entering steep terrain, consider pushing a bit of snow down first to see how the surface layers react. Depending on your experience, encountering small amounts of this soft running snow, or sluff, may feel acceptable, but stay alert for and avoid any larger amounts which could pose more of a threat to you.

    A small, shallow soft slab avalanche like one you could see on Monday.

    Photo: Irene Henninger

Avalanche Discussion

As we move away from the recent storm, very cold temperatures are settling into the region. Prepare for your outing with warmer layers than usual. Snow totals are surpassing 100 inches in the area, it’s a good time to start thinking about tree well and snow immersion and suffocation hazards (SIS).

Regions covered