Bulletin d’avalanche

Togwotee Pass

Bridger-Teton Avalanche Center
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Danger d’avalanche

Tue
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
Sans niveau
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Périmé — ce bulletin a expiré last year. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Triggering a large avalanche that fails on weak layers of snow buried 2-3 feet deep is possible in very steep terrain in the upper elevations. Give very steep, rocky, and wind affected slopes a wide margin today in order to avoid being involved in a dangerous avalanche. Avalanches are unlikely at the low elevations except for in isolated pockets of very steep terrain.

Problèmes avalancheux

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1.5–3

    Triggering an avalanche that fails on buried weak layers where the overlying slab is 2-3 feet deep is possible on very steep slopes over 35 degrees in the upper elevations. Signs of instability such as cracking, collapsing, or recent avalanches may not be present before triggering a dangerous avalanche. Multiple tracks on a slope do not indicate stability with this problem type. Large triggers such as a cornice fall or multiple riders on a slope increase the odds of triggering a persistent slab. Suspect terrain includes very steep, rocky, and/or wind affected slopes where thin spots exist making it possible for humans to impact buried weak layers.

    Persistent slab avalanches are capable of propagating widely across or up a slope. For this reason, it is not out of the question to trigger a larger hard slab avalanche with depths over 5 feet as a result of hitting a thin, shallow portion of the slope. Heavily wind affected slopes are where these avalanches could break deeper, such as this very large persistent slab on Lava Mountain that occurred on February 10th.

    The last human triggered persistent slab avalanche occurred on March 2nd in terrain similar to this.

    Photo: Dakota Richardson

Avalanche Discussion

Partly cloudy skies and breezy conditions will limit any wet snow problems around Togwotee Pass today. Surface crusts did not break down until late in the day yesterday and there was little to no loose snow available to move in steep sunny terrain.

The overall structure of the snowpack remains poor around Togwotee Pass despite the recent spring weather. Weak layers of sugary facets are still preserved 2-3 feet below the surface in the upper elevations. Weak snow exists in some shaded lower elevation terrain, but is generally lacking an overlying slab. A Large human triggered avalanche involving weak layers of buried facets occurred just over a week ago on Mount Leidy. Persistent slab problems are slow to change and this is certainly true around Togwotee. It is likely that this problem will be on the radar until later in the spring when melt cycles start to change the structure of layers deeper in the snowpack. For the time being, it is worth remaining vigilant around very steep and complex terrain.

If you see avalanche activity today, please consider submitting an observation HERE. Observations allow everyone to gain a better and more complete understanding of conditions. Thanks!

Régions couvertes