Avalanche forecast

West Slopes Central

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A change in conditions is in store for Wednesday. Small wet loose and wind slab avalanches could be encountered depending on your terrain choices.  Give steep, sunny terrain some room if you see signs of wet avalanche instability like rollerballs and pinwheels.

Avalanche problems

  • Loose Wet

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

    Rising temperatures and strong sun will set the stage for a round of wet avalanches. We are sure to see signs of instability with changing conditions. The size and extent of wet loose avalanches will be the question of the day. 

    Pay attention to slopes overhead and look for initial signs of instability like snow shedding from trees and rocks.  Rollerballs and pinwheels will be more plentiful as it warms up. Though initially small, wet avalanches could grow in size as the day grows warmer. Scale back your exposure to steep sunny slopes if you are seeing avalanches bigger and more widespread than expected.

    Be aware of cornices overhead that could shed with warmer temps. Shady slopes could begin to greenhouse if clouds stick around longer than expected.

    (1/20/2023)

    Wet loose avalanches getting near and crossing tracks made earlier the same day.

     

  • Wind Slabs

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

    The amount of fresh wind slab varies across the zone with the fattest crop probably found near Stevens and Snoqualmie Pass. Track wind drifted snow to find areas where a trigger-able slab could be hanging out. If you are traveling in high consequence, alpine terrain you should definitely do this.

    Look for the pattern of wind loading in the surrounding terrain. Given the current conditions, small cornices and other wind drifted features might be the best clues. Test slopes and hand pits can help you monitor differences in layering as you change aspects and gain elevation. Evaluate the bond of wind slabs and ease into steeper terrain - or just find a lower-angled line around areas like convex rolls where you are more likely to trigger one.

    (1/23/2023)

    Filled-in tracks are a sign the wind has been at work redistributing snow and possibly building new slabs.

    Photo: Irene Henniger

Avalanche Discussion

Windy and damp conditions were the headline in the southern half of the zone Tuesday. Stevens and Snoqualmie Pass recorded ridgeline wind gusts in the 30’s and 40’s and fresh, triggerable wind slabs were found (observation). Farther north less wind transport was noted. The Pan Dome weather station saw no meaningful wind in the last 24 hours. No new avalanches were reported in West North.

The biggest question mark regarding snowpack is if weak snow surfaces from last week were preserved under new snow in a few places. Take an extra minute or three to look at the interface between new and older layers before diving into consequential terrain. 

Regions covered