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

In steep, leeward terrain above 9,000 feet, skiers and riders could trigger dense wind slabs ranging in depth from 6 to 18 inches. Above 7,500 feet, large to very large persistent deep slabs lurk on a variety of aspects. Additional snowfall and warming temperatures may increase the likelihood of triggering both wind slabs and persistent deep slabs as the day progresses. Monitor weather conditions, and be willing to change your plans if conditions warrant. Below 7,500 feet, avalanche activity is unlikely in most areas.

Problèmes avalancheux

  • Deep Persistent Slabs

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

    Dangerous persistent deep slabs up to five feet in depth remain a concern on a variety of aspects above 7,500 feet. Since January 19th, between 4.5 and 5.5 inches of snow water equivalent has been added to the snowpack, and around 2.0 inches of that has occurred since Wednesday. While large triggers, such as snowmobiles or the release of a wind slab, are more likely 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. These slabs could propagate long distances and are likely to carry severe consequences to anyone involved.

  • Wind Slabs

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

    Strong westerly ridgetop winds continue to redistribute snow available for transport onto leeward slopes above 9,000 feet, and snowfall during the day will add depth and volume to these slabs. Up there, skiers and riders could trigger these dense, shallow wind slabs in steep, wind-loaded terrain.

Avalanche Discussion

A pulse of moisture in the strong northwest flow will bring periods of moderate to heavy snowfall overnight. Accumulations of 5 to 10 inches are possible by morning. Lighter snowfall during the day could bring another 2 to 5 inches to the mountains on Monday. Strong westerly winds will create areas of blowing and drifting snow. Cooler air will begin to move into the region. Temperatures will be in the 20s in the mountains and in the low to mid 30s in the valleys. The new snow and strong, gusty winds will be increasing the general avalanche hazard in the mountains and be creating dangerous avalanche conditions. Large to very large deep slab avalanches could be human triggered or release naturally with depths to 5 feet on a variety of aspects at the mid and upper elevations. Winds slabs 1 to 3 feet in depth could also be triggered by humans at the higher elevations in steep wind loaded avalanche starting zones, cliff areas and in steep couloirs and could step down to the December layer. The general avalanches hazard is expected to be CONSIDERABLE except at the lower elevations (below 7,500 feet) where avalanches are unlikely and the hazard is expected to be LOW. Excellent terrain analysis skills and conservative terrain choices are warranted. AVALANCHE ACCIDENTS INVOLVING BACKCOUNTRY USERS ARE LIKELY.

Régions couvertes