Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You might see small wind slab or wet avalanches depending on where you go in the mountains. Give steep, sunny terrain some room if you see signs of wet avalanche instability like rollerballs and pinwheels.

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    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.

    Wet loose avalanche in steep near treeline terrain. 

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    You can probably find a fresh wind slab if you look hard enough, but by Wednesday most will be well over a day old and difficult to trigger. It’s still worth tracking 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.

    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

Tuesday was a quiet one with few backcountry travelers and no new avalanche observations in West North. Signs of wind transport were found in exposed areas but new slab development was minimal. Calm conditions prevailed in observed terrain . Most aspects hold good riding conditions with 3-6” of light new snow on top of denser layers and rain crust. Upper snowpack structure is generally right side up. Solar aspects are a bit scratchier with new snow over sun crust. 

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. 

Regioni coperte