Bulletin d’avalanche

Tetons

Bridger-Teton Avalanche Center
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Danger d’avalanche

Alpin
3 · Marqué
Limite forestière
3 · Marqué
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 6 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Dangerous avalanche conditions continue to exist at the mid and upper elevations. On a variety of aspects and elevations, backcountry skiers and riders still have the potential of triggering large to very large persistent slab avalanches in steep terrain. Although these slabs have become less sensitive to triggering, the danger rating remains elevated due to the widespread distribution of the weak layer problem and the difficulty in determining which slopes remain prone to failure. Also, if triggered, these avalanches could be large to very large in size and carry dire consequences to anyone involved. At lower elevations, the snowpack is weak and smaller human triggered avalanches remain a possibility in steep terrain.

Problèmes avalancheux

  • Persistent Slabs

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

    Faceted weak layers are prevalent throughout the region however the amount of that weakness and the amount of cohesive snow over it varies greatly. This variability requires an extra margin of safety; now is not the time to let your guard down and become complacent. In higher elevations, slab depths could reach four feet while at lower elevations slabs are more likely to have depths of one foot. Failure is more likely to occur when a thin, weak spot on a slope is impacted or by larger triggers such as snowmobiles or groups of people. Under these conditions, do not trust a few tracks as an indication of stability

Avalanche Discussion

A Winter Weather Advisory is in effect through 11pm Wednesday evening. As moisture increases with the incoming system, snowfall will develop overnight. A few inches of snow is expected by sunrise with storm totals by late Wednesday of five to ten inches in the Teton and Southwest areas, and four to six inches in the Togwotee Pass area. Warmer air is associated with this system and some of the precipitation may fall as a mix of rain and snow in the valleys. Upper elevations are to have highs in the mid-twenties. Strong west to southwest winds are to accompany the event with averages of 25-40 mph. The general avalanche danger is likely to be Considerable in the Teton and Southwest Trails areas above 7500 and Moderate below that elevation. In the Togwotee Pass area, it will likely be Moderate at all elevations. If snowfall and/or winds are higher than forecast the danger rating may increase. Regardless of the rating, there will be increasing danger throughout the day tomorrow as new snow and wind form sensitive surface slabs on the existing snow surfaces. The likelihood of triggering deeper instabilities will also increase during the day as potentially an inch of moisture is quickly added to a snowpack with widespread weaknesses. Slab depths involving these old layers could be as much as four or five feet at higher elevations and up to two feet deep at lower elevations. Tomorrow is a day to have a stepping back mindset and avoid steep avalanche terrain. Conservative decision making is the only way to navigate around this unique situation where, to varying degrees, weak snow layers can be found on all aspects and elevations.

Régions couvertes