Bulletin d’avalanche

West Slopes Central

Northwest Avalanche Center
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Danger d’avalanche

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

Points saillants

You can trigger slab avalanches on steep slopes as light snowfall continues on Sunday. Avoid terrain greater than 35 degrees, especially on wind loaded features at higher elevations.

Problèmes avalancheux

  • Storm Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1–2

    Expect natural and human triggered slab avalanches to occur on steep slopes. You will find them most reactive in upper elevation areas where wind loading occurred. Avalanches could break within layers of new and wind drifted snow, or on variable old snow surfaces buried Thursday (3/18). Pay attention to the layers beneath the new snow, as melt freeze crusts were present before the storm on the southerly half, while direct northerly aspects above approximately 4500ft held dry snow. Weak snow may have formed at the surface of the dry snow during the high pressure over the last week, so avalanches may fail easier at that interface. 

    Dig down to the new snow/old snow break to investigate how readily snow slides at the interface, or on layers within the new snow. Seek out small slopes before committing to consequential terrain. Avoid steep, unsupported slopes and start zones with signs of unstable snow, especially if wind drifted.

    An example of a widely propagating storm slab avalanche.

Avalanche Discussion

Unsettled weather is forecasted to continue in the coming week, bringing a welcome change to the sudden onset of spring conditions. Saturday, conditions remained warm and wet loose avalanches occurred at mid to lower elevations. A hiker entered an avalanche observation from their hike up to Lake 22. Despite its seemingly benign nature, avalanches occur even in the vicinity of some low elevation hiking trails in the area. You can check the observation out HERE.  Temperatures should cool enough into Sunday for the wet loose danger to drop.  On Sunday, more precipitation is forecasted for the northerly reaches of the West Central zone, but the avalanche danger may not be as elevated in the southerly portion of the zone where we will see less precipitation.

Keep cornices in mind as these already large features are continuing to grow. They could drop onto slopes below acting as huge triggers. Stand back from cornices along ridgelines and minimize overhead exposure to these features. Several large glide cracks and a few glide avalanches were observed recently as well. Cooling temperatures should limit glide activity for now, but these avalanches are difficult to predict. If you notice these crevasse-like cracks in the snowpack, avoid slopes beneath those features.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Régions couvertes