Bulletin d’avalanche

Tetons

Bridger-Teton Avalanche Center
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Danger d’avalanche

Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 9 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

At the mid and high elevations, the chance continues for skiers or riders to trigger avalanches involving weak snow layers that were buried in December. As new snow falls, the sensitivity of these slabs will increase and new surface slab hazards will develop this afternoon as heavy snow and wind combine with yesterdays light snow to create wind slabs at the higher elevations. Avalanches below 7500 feet are unlikely today. Safe travel in these conditions requires careful snowpack and terrain evaluation.

Problèmes avalancheux

  • Deep Persistent Slabs

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

    Dangerous deep slab avalanches continue to be a hazard on all aspects at the mid and upper elevations. Failure of these layers could require larger triggers such as groups of people or snow machines, however, failure could still occur by a single person if a particular weak spot on a slope is hit. These slabs could propagate long distances, have depths to four feet and could carry severe consequences to anyone involved.

  • Wind Slabs

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

    As the day progresses at high elevations, new soft slabs will form on steep terrain prone to wind loading, particularly near ridge lines, peaks and cliff areas. These slabs are forming on recently fallen light snow over denser layers of settled snow and sun-crusts. Slab depths of eight to ten inches are possible by days end.

Avalanche Discussion

Northwesterly flow aloft will bring the next in a series of Pacific disturbances through the region overnight. After a brief midday lull, a second disturbance will move through in the afternoon. Overnight lows in the mountains will be in the upper teens before rising into the upper 20s during the day. Westerly ridgetop winds will range from 20 to 30 miles per hour.The general avalanche hazard is expected to be MODERATE above 7,500 feet on Saturday. Skiers and riders could trigger newly and recently developed wind slabs in steep, leeward terrain near high elevation ridgelines. These slabs, which are most likely to occur in the Tetons, could range in depth from 6 to 18 inches and fail on sun crusts, density breaks or down to a layer of surface hoar buried on January 19th. Dangerous persistent deep slabs up to five feet in depth lurk on a variety of aspects above 7,500 feet. While large triggers, such as snowmobiles or the release of a wind slab, are more likely to be able to cause failure of these slabs, the weight of a single person could still act as a trigger if a shallow weak zone is encountered. Below 7,500 feet, backcountry travelers might be able to trigger an isolated pocket of slab in very steep ravines and gullies that are mostly shaded from the sun.

Régions couvertes