Bulletin d’avalanche

Gunnison

Crested Butte Avalanche Center
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Danger d’avalanche

Mon
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Points saillants

A little fresh snow and strong winds overnight are combining to form fresh wind slabs. You could encounter this avalanche problem at both near and above treeline elevations, but given the low snow amounts the primary concerns will be at above treeline elevations. Keep an eye out near ridgelines and on cross-loaded terrain features, for these thin soft slabs. Large persistent slab avalanches breaking deeper into old snow are unlikely to human trigger in the big picture view. The most suspect areas for this avalanche problem would be steep slopes with variable snowpack depths and many trigger points, or avalanche paths that previously ran back in Febuary and have refilled with a new slab. 

Problèmes avalancheux

  • Wind Slabs

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

    New snow amounts overnight look to average 2 to 4". Since midnight, 12,000ft winds have averaged in the 30mph range, with gusts into the 50's. Strong wind gusts were also mixing down to lower elevations. Given the low new snow numbers, the best concentration of small wind slabs will be at above treeline elevations. In areas that received 4" of new snow, you may be able to encounter this avalanche problem at near treeline elevations as well.  

    Example of a small, shallow wind slab from the archives.

  • Persistent Slabs

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

    Skiers and riders have triggered a handful of soft slab avalanches that released on buried weak layers in the middle to upper snowpack last week (Example A, Example B, Example C). Currently, the most concerning areas for this avalanche problem will be in steep terrain with variable snowpack depths creating more trigger points. Or in avalanche paths that ran back in February and are finally accumulating enough snow to form a new slab. It may be dangerous to gather snowpack depths in start zones, so keep an eye out for old crown lines or for slopes that look like they have a below-average snowpack. 

    3/18: A skier was caught by surprise by this persistent slab on Mt. Axtell.

Avalanche Discussion

The arrival of the cold front overnight removed wet avalanche concerns. The strong overnight winds didn't have much old snow for transport, so last night's new snow would be the main source for new wind slabs. With only about 1 to 4" of new snow across the whole forecast areas, these new wind slabs are expected to be small. The distribution of this avalanche problem is isolated at near treeline elevations and a bit wider or "specific" distribution at above treeline elevations. In many areas, this new snow will probably only be dust on crust, or a little extra soft snow on northerly-facing slopes. 

The persistent slab avalanche problem was bumped to "possible" after last weekend's storm. In recent days we have seen that problem trending towards "unlikely". However the warm temperatures in recent days were keeping those slabs soft, and in some cases wet. With the arrival of cold weather again the likelihood scale was dropped one notch. The avalanche problem description highlights the main areas of concern. If you are riding steep or extreme terrain, you should still be considering the terrain consequences of a large avalanche. 

There isn't much snow in the forecast heading into Monday morning. The weather forecast had a little uncertainty in timing and new snow amounts for tomorrow. At the moment we'd expect similar conditions heading into tomorrow. However, if the weather forecast changes for more snow then we may see some changes.

Régions couvertes