Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Highlights

Dangerous avalanche conditions are expected on Saturday as fresh snow and strong winds form sensitive slabs that are big enough to injure or kill a backcountry traveler. Stick to low-angle terrain and avoid steep, open slopes to manage the hazard. While avalanches will be most likely during and just after heavy snowfall, continued winds and moderate snow will keep conditions hazardous throughout the day.

Avalanche problems

  • Storm Slabs

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

    In favored areas such as Crystal Mountain and the volcanoes, a foot of snow overnight Friday into Saturday could be followed by another 6” or more during the day. This equation is pretty straightforward: new snow + strong wind = avalanches. Thorough route planning and conservative decision-making are essential on Saturday. While we don’t expect a widespread natural avalanche cycle, isolated natural avalanches are possible. Human-triggered and natural avalanches could entrain recent snow and slide on the slick 12/7 crust.

    Though the likelihood and consequence of an avalanche will increase on any slope where the wind builds a thicker slab, any terrain steep enough to slide should be treated as suspect and warrants your assessment. Red flags like avalanches and shooting cracks signal a snowpack ready to avalanche if you venture into steeper terrain. Uptrack tests, pole probes, jumping on safe test slopes, and hand shears are all useful tools to help with your assessment.

    When snow stability is the question, terrain is the answer. The safest option is to stick to low-angle, sheltered terrain while you give the snowpack another day to adjust to this new load.  

    (12/20/2021)

    An example of a storm slab avalanche that may be easily triggered on Saturday. 

    Photo: Andrew Kiefer

Avalanche Discussion

We’re in for a stormy start to the weekend in the WA Cascades. As of Friday evening, a few inches of fresh snow are being actively transported by gusty winds at Crystal Mountain and Mount Rainier, with the main event just knocking on the door. Skiers have already triggered small wind-loaded pockets of snow, offering a preview of the likely conditions on Saturday.

Snow totals will vary significantly across the zone. Crystal appears to be the overall winner, especially overnight Friday into Saturday, while the volcanoes could see more accumulation during the day on Saturday. Locally higher snow totals will increase the likelihood and consequences of avalanches. Meanwhile, White Pass is expected to receive less snowfall and as a result, avalanche danger will be a notch lower than for the rest of the zone.

Recreating during a storm can be quite rewarding, but it requires careful route planning, knowledge of the terrain, and appropriate terrain selection to do so safely. If you take that approach and avoid being on or under steep slopes, you can have a safe and lovely day in the mountains. If you choose to enter terrain capable of producing a slide, you’ll need to assess the snow stability for yourself. This can prove tricky and always involves uncertainty. Poor visibility could increase the challenge as your eyes are a primary tool for identifying wind slab formation. Keep in mind that fast-running sluffs are also possible in steeper terrain.

If you get out, please share an observation with us. Have a safe and enjoyable storm day!

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