Bulletin d’avalanche

Tetons

Bridger-Teton Avalanche Center
Voir sur la carte

Danger d’avalanche

Tue
Alpin
3 · Marqué
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
Open full map
Périmé — ce bulletin a expiré 6 months ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Human-triggered avalanches 1-3 feet thick may be likely as wind moves snow.   Look for drifting and plumes of snow in the air at ridgetops as indictors for wind slab growth.  While the chance for triggering a deeper weak layer has diminished, it's a good idea to dig to look for it before committing to terrain over 35 degrees. 

A persistent slab avalanche was triggered  yesterday near Prater Canyon in the Salt River Range. This observation is a great reminder that it is still possible to trigger an avalanche on the January drought layer.

Problèmes avalancheux

  • Wind Slabs

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

    Twelve to fifteen inches of snow fell over the past week.  During this time, winds were relatively light. In the past 12 hours, southwest winds have ramped up to 45-50 mph,  and will continue at similar speeds  through the day, potentially ripping  up ice crust where it exists and moving loose snow beneath.  Slabs may be 1-3 feet deep, are likely to be hard and may be sensitive to triggering, especially if they bond poorly to existing ice and rime crusts.  You are most likely to find these slabs above 9,000' where significant fetch exists. Keep an eye on snow shower activity this morning which could add 2-3 inches new snow to this problem. The degree to which the rime and ice crust contain loose snow on the ground will determine the size and likelihood of triggering a wind slab. 

     

  • Persistent Slabs

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

    Weak snow from January lies 2-4 feet below  the snow's surface. Though this drought layer has gained strength with time, triggering a large and widely propagating avalanche remains possible, especially in very steep terrain above about 8,000'. This problem continues to deserve respect, especially in high consequence terrain and places where the slab may be thin enough for the weight of a person or snowmachine to hit the weak layer. Avalanches on this layer are currently stubborn to trigger and unlikely to produce any warning signs like collapsing.

    Cornice Fall: Large triggers such as a falling cornice could trigger a larger avalanche. While unlikely, it's a good idea to give cornices some space.

     

    2/28/2026

    A large avalanche south of JHMR that failed on weak snow in the middle of the snowpack. The avalanche was likely triggered by a piece of falling cornice. Most recent persistent slab avalanche events have occurred on the west and south side of the Tetons.

Avalanche Discussion

Recent warm emperatures, some sunshine and a freezing rain and icing event have resulted in a mixed bag of surfaces. You'll find lots of refrozen snow and crusts around on solar slopes and to mid-elevation northerlies as well.  A lot of uncertainty exists in the forecast due to unknowns regarding the distribution and durability of ice lens and rime crusts on the surface. Rain showers 36-48 hours and some clearing skies and warm temperatures yesterday have no doubt made snow on the ground harder to move but the degree to which that is true remains uncertain. 

Thanks for submitting your observations. Observations like the one from Prater last night can save lives!

Régions couvertes