Bulletin d’avalanche

West Slopes North

Northwest Avalanche Center
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Danger d’avalanche

Sun
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 5 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Remain alert for the isolated avalanche that you could trigger on upper elevation wind-loaded slopes.  Search for thicker feeling snow and wind-affected surfaces and avoid these areas in steep terrain.  Expect to encounter variable surfaces at lower elevations, and refrozen snow on south-facing terrain.

Problèmes avalancheux

  • Wind Slabs

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

    Skier triggered wind slab avalanches were reported Friday. Reactive wind slabs will remain lurking in isolated pockets of upper elevation terrain.  Increasing wind as the day continues could contribute to new slab development.  You might only find them a few inches deep, or possibly up to a foot deep. Pay attention to snow surfaces to identify signs of loading. Search for drifted snow, such as wind lips or small scoops. Larger smooth surfaces may also have subtle textured features indicating wind loading. It could also be the case that old wind-loaded slopes may have had lower density, non wind-affected snow coating them, making them more difficult to identify. Feeling for stiffer snow under your feet is usually  a good indicator. Some of the reported avalanches were in low-density snow, making identifying by feeling a bit more challenging. 

    Consider avoiding slopes greater than 35 degrees on above treeline slopes where you encounter the wind slab indicators previously mentioned. If you venture out in suspect areas, keep an escape route in mind in case the slope you're on does slide. 

    Recent wind slab avalanche (likely human triggered)  in the Baker Backcountry. 

    Photo: NWAC Public Obs

Avalanche Discussion

Freezing levels will rise to 5000ft Saturday morning before dropping throughout the day. There is a chance that low to mid-elevation snow surfaces could become moist. Increasing winds, however, might keep surfaces firm.

Several backcountry travelers observed weak snow surfaces on Friday (surface hoar and near surface facets). Saturday afternoon snow will begin falling, with freezing levels dropping to 3000ft overnight.  If the persistent weak layers stay preserved as snow falls, very touchy avalanche conditions could occur. If you're out on Saturday and notice whether surface hoar is still present or it's being destroyed by warm temperatures or wind, let us know by submitting an observation HERE.  This will help us paint a better picture of avalanche conditions as more snow falls. 

Régions couvertes