Bulletin d’avalanche

Tetons

Bridger-Teton Avalanche Center
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Danger d’avalanche

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

Points saillants

Watch for obvious signs of wind drifted snow on steep slopes in the upper elevations where triggering an avalanche is possible. In addition, pay attention to snow surfaces warming by the afternoon as the potential for wet loose avalanches will increase on slopes facing the sun. 

Problèmes avalancheux

  • Wind Slabs

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

    Increasing W/NW wind has formed slabs less than a foot deep in the upper elevations, particularly above 10,000’. The distribution and reactivity of these slabs will increase as you travel higher in elevation. Identify wind drifted snow by looking for cracking or stiffened surfaces and large pillows. Look for these clues on open and exposed terrain on leeward S-E aspects as well as confined features such as couloirs or below cliff bands. 

    Cornice Falls: Increased temperatures and sunshine will destabilize cornices. Give cornices a wide margin of safety and be careful along ridgelines as they can break further back than expected. Limit exposure under cornices where natural falls could occur and trigger a very large avalanche on deep weak layers as reported on The Wedge yesterday. 

    (4/8/2024)

    Wind slab adjacent to dry loose at 10,500' on a steep ESE aspect with a depth of approximately 10". 

    Photo: Alex Drinkard

  • Loose Wet

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

    Warming temperatures combined with clear skies and strong solar influence today will destabilize recent snow creating wet loose avalanches by the afternoon. These avalanches will be confined to slopes facing the sun with increased activity expected around rock features that heat up surrounding snow surfaces. Avoid steep slopes if you encounter wet snow and are sinking significantly into a slushy snowpack. Plan your travels accordingly to seek cooler and shaded aspects by the afternoon. 

    (4/4/2024)

    A D1.5 wet loose avalanche. Wet loose avalanches often start at a point, near exposed rocks or trees, and fan out. 

    Photo: Cameron Galt

Avalanche Discussion

W/NW wind increased to 19-29 mph (JHMR Summit weather station) from the evening of the 9th to morning of the 10th during a 10 hour period. This has created isolated wind slabs in the upper elevations. Terrain above the forecast boundary of 10,500’ experienced the most significant amount of wind drifted and scoured snow surfaces. Keep this in mind if you plan to travel to the high peaks today or tomorrow and step into more challenging or complex terrain. Remember to do your own research on changing weather conditions prior to alpine starts before the forecast is published. 

Temperatures are expected to reach the 30-40°F in the upper elevations and 40-50°F in the lower to middle elevations today. Watch for increased wet loose activity as recent snow begins to shed on slopes facing the sun. These avalanches will be small but could easily knock a rider off their feet and be consequential in complex terrain. Steep southeast slopes will warm first followed by south and then southwest. Lower elevation slopes will also warm earlier in the day. Temperatures last night dropped to 20-30°F enabling a solid refreeze.

A very large avalanche was reported yesterday near Grand Targhee on the Wedge at 9600' on a N aspect. This avalanche was likely triggered by a large cornice fall and failed on weak layers buried deep in the snowpack. Human triggered avalanches are very unlikely, but watch for any overhead hazards of cornices. Identify terrain below large cornices and limit exposure to manage this problem. 

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