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 2-3 feet deep that fails on buried weak layers is possible in very steep terrain above 9,000’. Give steep, rocky, and wind affected terrain a wide margin to avoid involvement in an avalanche today. Avalanches are unlikely in the lower elevations except for isolated pockets of very steep terrain.

Problèmes avalancheux

  • Persistent Slabs

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

    Slabs overlying weak layers buried 2-3 feet deep remain possible to trigger on very steep slopes over 35° in the upper elevations. Signs of instability such as cracking, collapsing, or recent avalanches may not be present before triggering a large, dangerous avalanche. These avalanches are capable of propagating far across or upslope making escape difficult. Multiple tracks on a slope do not indicate stability with this problem type. Large triggers such as cornice falls and groups increase the odds of impacting buried weak layers. Steer clear of very steep, rocky, and wind affected slopes to avoid dealing with this avalanche problem today.

    Yesterday, a large avalanche was triggered by a snowmobiler on Mount Leidy. This avalanche likely involved persistent weak layers and is evidence that riders still have the potential to impact these layers.

    (2/27/2025)

    Steep, rocky, and wind affected terrain above 10,000’ near Togwotee Pass. The boundary between wind scoured and wind loaded features are the most likely places to trigger a persistent slab avalanche.

    Photo: Bridger-Teton Avalanche Center

  • Deep Persistent Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Unlikely
    Taille
    2–3

    Weak snow buried 5 feet deep exists near the ground above 9,000’. Triggering an avalanche at this depth is very unlikely but not impossible.

    On February 10th, a rider stepped off their sled and triggered a very large avalanche that failed near the ground on Lava Mountain. This avalanche was triggered where the overlying slab was thin making it possible for the rider to impact the underlying weak layer. Manage this problem the same way you would manage weak layers in the middle of the snowpack by avoiding very steep, rocky, and wind loaded terrain.

     

    (2/11/2025)

    The crown of the recent unintentionally-triggered avalanche on the E face of Lava ~10,400'.

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

Buried weak layers continue to show reactivity. The human triggered avalanche on Leidy yesterday as well as this observation from Breccia suggest that there is still potential for avalanches involving these layers. The likelihood of triggering a persistent slab avalanche has decreased today with colder weather, however, very steep terrain at the upper elevations should be evaluated carefully to avoid triggering one of these dangerous avalanches. 

A weak storm system is approaching the Togwotee area with 2-4 inches of new snow and minimal wind expected by evening. This should do little to increase the avalanche hazard but be on the lookout for isolated pockets of wind slab in very steep terrain at the highest elevations.

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