Bulletin d’avalanche

Southeast Mountains

Crested Butte Avalanche Center
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Danger d’avalanche

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

Points saillants

Keep an eye out for small slabs on previously wind-loaded terrain features, such as near ridgelines and cross-loaded slopes lower in the terrain. These slabs will include old hard slabs that formed early in the week and soft slabs that may have formed yesterday, with what little snow was available for transport. Observers yesterday were able to find examples of these avalanche problems in both forecast areas (1&2). The softest snow surface, and probably the best skiing and riding, can be found in wind-sheltered locations with no slab avalanche concerns. 

Problèmes avalancheux

  • Persistent Slabs

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

    Over the past week, a couple of small storms and associated wind events have formed new slabs out of what little snow was available for transport. These slabs will commonly be found near ridgelines and in concave terrain features such as cross-loaded gullies or rollovers in the terrain. In a few isolated areas, they may be found on cross-loaded westerly aspects. These slabs are often hard and stubborn to trigger. Consider avoiding wind-loaded terrain features if you are unsure of the potential avalanche conditions or find the problem difficult to manage. 

    In very isolated areas, an avalanche could release several feet deep on weak layers near the ground. These areas would have needed to retain the full-season snowpack without that snowpack having been removed by the widespread avalanche cycle that occurred in late November. 

     

     

    You can see the outline of a slab that tried to displace but didn't move far downhill. This is a cross-loaded terrain feature at 11,500ft. Note the wind-eroded snow by the skier and smoother wind-loaded snow in front of the skier. 

Avalanche Discussion

The avalanche danger has been riding the line between LOW and MODERATE this week. This is because the old snowpack is very weak due to its shallow depth and the prolonged drought following Thanksgiving. When we have such a weak foundation, even small weather changes can temporarily make new avalanche problems more reactive. So, to start the weekend, we'll keep an eye out for any new slab formation over these old weak layers. 

Snow accumulation in the Gunnison River Basin has basically flatlined since November 28th. Click here to see the graph. This extended drought has greatly reduced concerns for avalanche activity involving the Thanksgiving Slab or Gizzard Blizzard. We have now transitioned into a period where each small storm we receive creates a new round of wind-related slabs over the old, weak snow surface. The NW wind event that started of the week, did more wind erosion than slab formation. The slabs that are left over from this event are covered in the current persistent slab avalanche problem. These slabs formed over small near-surface facets and, in some cases, on large depth hoars where that slab developed on an old bed surface from the avalanche activity back in November.  An example of some of these slabs can be seen in this observation on Thursday. 

Looking ahead, the next storm on Sunday is looking like a dud. So unless there is some notable new wind slab formation that is observed from this last storm, the avalanche danger will again be on a decreasing trend. 

Régions couvertes