Bollettino valanghe

West Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Sun
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 can trigger an avalanche at mid and upper elevations where wind transported new snow forms unstable slabs. Monitor the wind loading pattern in the terrain you travel and steer around steep, freshly loaded slopes. The south side of Mt. Baker and the Baker Backcountry may experience greater danger during periods of heavier snowfall - be ready to change your plan based on your own observations. 

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    A new crop of wind slab could form with gusty winds and moderate snowfall Friday night and Saturday. Though dense, wet new snow at treeline could limit wind slab development, look for drier snow and more reactive slabs as you gain elevation. 

    Pay attention to the pattern of wind loading by using scoured snow surfaces, cornice-like features, and changes in snow texture to suss out where wind slabs could be hiding. Blowing snow might just show you exactly which slopes are loading up. Evaluate the bond of wind slabs before committing to steep terrain - or just steer around steep wind loaded slopes to reduce the likelihood of triggering an avalanche.

    If you experience heavy snowfall be ready to find unstable slabs in all steep terrain, not just in wind loaded areas. Fall back to a more conservative plan if you find conditions different (as in more snow, stronger wind, etc.) than anticipated. 

     

    (1/6/2023)

    Wind affect on the east side of Herman Saddle.

    Photo: Julz Holder

Avalanche Discussion

Wet avalanche activity could be a factor on Saturday with snow levels hovering just below treeline. Pay attention to slopes overhead and look for signs of instability like pinwheels, rollerballs, or snow shedding from trees and rocks. Don’t linger directly under steep slopes if you start seeing any of the above.

Friday was pretty quiet in West North after a warm storm the previous night. Most areas picked up about 0.5” of precip as a mixture of rain and snow near treeline. Heather Meadows ended up with 1.5” of H2O with the majority as rain and 3-4” of new snow at 4500-5000’. Strong winds with gusts to the low 50’s were recorded and wind affected snow surfaces are everywhere. 

Reported avalanche activity included a large, naturally triggered slab avalanche that likely occurred early Friday morning (judging by the bit of new snow over the debris). It appears to be triggered by sluff or cornice fall from above. A few small wet avalanches were reported as well.

There is currently 1-3’ of snow over the rain crust buried in late December. The upper snowpack is reported as well bonded with no layers of concern.  Instability has been limited to the most recent new snow and wind slab layers.

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