Bulletin d’avalanche

Northwest Mountains

Crested Butte Avalanche Center
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Danger d’avalanche

Fri
Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
3 · Marqué
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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 conditions remain dangerous and human-triggered avalanches are likely.  Any steep slope with weak snow beneath Tuesday's storm snow should be treated with caution.  You can remotely trigger avalanches from below or adjacent features.  To reduce your chance of triggering an avalanche avoid travel on or below steep slopes that have weak snow beneath the recent storm.

Problèmes avalancheux

  • Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Likely
    Taille
    1.5–2.5

    Tuesday's storm formed slabs 1 to 2 feet thick above a widespread persistent weak layer.  A natural avalanche cycle occurred on Tuesday and observers reported many avalanches large enough to bury and kill a person.  The most dangerous terrain faces west through north through east as these aspects contain the thickest and most continuous weak layer however, some southerly-facing slopes also have the weak layer at upper elevations. 

    A widely-propagating avalanche that failed during the recent natural cycle; a good representation of the deadly size potential.

Avalanche Discussion

The story of the current dangerous avalanche conditions can be summed up quickly.  Early season snowfall in October and early November left a thin, but a continuous blanket of snow across many aspects and elevations.  A prolonged dry spell during November allowed the early season snow to weaken through the faceting process.  Tuesday's storm buried the persistent weak layer with slabs 1 to 2 feet thick and produced a widespread avalanche cycle.  Take a look through the CBAC's observation page (or the media gallery below) to view the natural and human-triggered avalanches from the past two days. Most avalanches occurred on the north half of the compass, but some sunny slopes harbor the weak layer as well.

Due to the well-developed nature of the weak layer, conditions will not improve quickly; observers reported "rampant collapsing" and remotely-triggering an avalanche from 250 feet yesterday.  Do not expect conditions to be any different today.  The simple solution is to avoid avalanche terrain if you find 10 inches or more of recent storm snow resting above older, weak snow.

An Avalanche Watch has been issued in anticipation of very dangerous avalanche conditions developing on Friday.  A intense, and quick-hitting storm will impact the Crested Butte area on Friday.  This storm is expected to push the danger HIGH and cause another natural avalanche cycle.

EVENTS:

  • Avalanche Awareness Night is December 3rd and Beacon Brushup is December 4th.  Details here.

Régions couvertes