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 9 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

DANGEROUS avalanche conditions exist in the backcountry today. Significant snowfall and strong winds have formed recent wind slabs and has further stressed deeper weaknesses in the snowpack. A single skier or rider could trigger either of these instabilities today causing slides that could cause injury or death. These slides, that can be small to very large, can be found on a variety of aspects at the mid and upper elevations. Cautious route finding and conservative decision making is essential today. At low elevations, activity is limited to north aspects between 7000 and 7500 feet, however travelers at low elevations also need to be wary of exposure to run out zones when under large avalanche paths. Yesterday there were several close calls with people being caught in slides but not injured. Many natural, human, and explosive triggered avalanches were reported. One of the most significant events was the very large slide on the Ullr path on 25 Short in GTNP that ran naturally from 9700 feet to the valley trail and had a five foot crown.

Problèmes avalancheux

  • Deep Persistent Slabs

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

    Slab avalanches that have the potential to be very large and involve buried weak faceted snow laying over hard crusts formed in late November could be triggered with depths of two to five feet on a variety of aspects. These slabs could be triggered by a single person, release after the initiation of a wind slab, or possibly release naturally as temperatures warm today. Consequences of being involved in such a slide are likely to be very severe.

  • Wind Slabs

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

    Heavy snowfall and strong winds that have varied from the south to northwest have formed sensitive wind slabs on a variety of aspects. These slabs will be very sensitive to human triggers today and could have depths to over three feet. Once triggered these slabs could cause failure of deeper layers in the snowpack. Periods of direct sunshine and warming temperatures will increase the sensitivity of these slabs today.

Avalanche Discussion

Skies will continue a clearing trend as high pressure builds over the region. Overnight lows in the mountains will be in the mid-teens before rising into the upper 20s during the day. Northwesterly ridgetop winds will range from 15 to 30 miles per hour.Dangerous avalanche conditions exist, and the general avalanche hazard is expected to be Considerable above 7,500 feet on Sunday. Skiers and riders are likely to trigger recently developed wind slabs up to three feet in depth on steep, avalanche-prone slopes. Much higher consequence slides failing on the December drought layer could be initiated directly by backcountry travelers or indirectly after the release of the aforementioned wind slabs. These large to very large slides, which could also release naturally and be up to five feet in depth, are likely to be unsurvivable. During the day, warming temperatures and sunshine will increased the likelihood of both the recently developed wind slabs and the deep persistent slabs, particularly on sunlit aspects. Don’t let sunshine and fresh powder cloud your judgement; expert snowpack examination and a very conservative approach to terrain analysis will remain essential for safe travel in avalanche terrain on Sunday. Below 7,500 feet, skiers and riders could trigger smaller slides. There, the runout zones of large, active slidepaths should also be avoided.

Régions couvertes