Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Rain, snow, and extreme winds will create dangerous avalanche conditions at all elevations Sunday. Large avalanches will be easy to trigger on slopes 35 degrees and steeper. Choose conservative terrain and minimize your exposure to overhead hazard.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    2

    A few inches of wet snow will accumulate overnight before temperatures cool and heavy snowfall begins Sunday morning. Expect 10-12+ inches of new snow above 4000ft by Sunday night. Strong to extreme southwesterly winds will blow through the forecast period. Conditions will be very dynamic. You may encounter lower avalanche hazard in the morning hours but be prepared for rapid change as precipitation rates look to increase to 1 inch of snow per hour through the evening. Large natural avalanches are even possible late in the day in the alpine. Watch for obvious signs of unstable snow like recent avalanches, shooting cracks, and collapses. Cornices are already overbuilt and will continue to grow in the next 24 hours. They could easily fail in conditions like these acting as huge triggers on slopes below. Steer around open slopes greater than 35 degrees with signs of wind loading. Minimize exposure to overhead hazard and choose low-angled, sheltered terrain while the storm runs its course.

    (12/31/2020) Example photo of a large natural avalanche in wind drifted snow below a corniced ridgeline.

  • Loose Wet

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

    Snow levels will hover near 4500ft overnight before dropping to 1500ft Sunday evening. The potential for loose wet avalanches will exist in the morning hours and will likely diminish by afternoon. Before temperatures cool, anticipate loose wet avalanches within new snow or anywhere you encounter heavy rain. Steer around slopes 35 degrees and steeper with evidence of wet snow like rollerballs, pinwheels, or sticky surface snow.

    (3/26/2021) Rollerballs and small wet loose avalanches at lower elevations in the Deer Creek drainage.

Avalanche Discussion

Expect rising avalanche danger as a potent storm builds fresh slabs and cornices over the next 24 hours. Blustery whiteout conditions will make travel difficult. New snow will fall on a variety of old snow surfaces including moist snow, breakable crusts, and dry settled powder. Extreme winds from the south and west will transport snow onto leeward slopes. Human-triggered avalanches are likely on slopes 35 degrees and steeper. Natural avalanches may even occur in alpine start zones by Sunday night and grow large. Avalanche activity may only involve new and wind-loaded snow, but it is not out of the question to see avalanches break several feet thick within recent storm snow received March 18-24. In addition to fresh slabs and loose wet avalanches, keep glide avalanches in mind. We could see more of these avalanches with heavy rain at low elevations on Sunday, and/or with warming and sunshine during the upcoming week as high pressure arrives. Watch out for these crevasse-like cracks in the snowpack, and avoid travel on or below steep slopes where they exist.

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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