Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 4 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Avalanche danger may still be remaining moderate, however you can expect to be able to find and trigger more avalanches than was the case in the last few days. Overnight wind and snow will likely lead to peak instability early in the morning, and it's possible that you could find and trigger wind slab avalanches in the new snow on Friday. For your day's outing search for stiffer, wind drifted snow deposits and steer around them on steep slopes, although If more snow or wind than expected occurs, err on the more conservative side with your travels.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    A storm is forecasted to bring 6-8" of snow and moderate to strong winds overnight. Instabilities will likely peak early morning before snowfall rates and wind decreases. You may find wind slabs a foot or deeper in the new snow, where it could be possible for you to trigger a small or mid-size avalanche.  If more snow falls or wind redistribution occurs than expected, avalanche danger could be higher than forecasted. 

    Search for newly drifted snow in the usual suspect locations like on the leeward sides of ridgelines, in gullies and around rocky outcroppings. Drifts could appear as smooth pillows or textured surfaces, and feel slightly stiffer than nearby non wind-affected surfaces. If you experience long cracks shooting out from under you, that's an indicator of weakness in the new snow layer, and one of the best clues to avoid nearby steep slopes. Friday's an excellent day for checking how well the new and old snow layers are bonded by using hand shears. Small test slopes are also a good way to test for shallow wind slabs. In areas that you find wind slabs or see other indicators of weak snow, steer around slopes greater than 35 degrees. 

Avalanche Discussion

Lower elevations may have moist snow and we could see rollerballs or small wet loose avalanches on steep slopes. We suspect rain fell to higher elevations at the start of the storm on Thursday evening, so a moist interface might exist beneath the new snow, which could mean the new layer may bond better, although that waits to be seen. Dry loose avalanches may occur in steep, non-wind affected terrain at upper elevations during your day on Friday.

Avalanches that occur will probably fail within or just under the new snow, although at above treeline elevations there's a small chance that avalanches could fail deeper, on few-day-old slabs. Another factor to consider for Friday is that slabs could slide easier on south-facing surfaces where previous sun crusts formed. If you have any doubt about conditions or find more reactive slabs than you expect, you can always detour towards lower angle terrain. 

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