Boletín de aludes

Snake River Range

Bridger-Teton Avalanche Center
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Peligro de aludes

Thu
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
3 · Notable
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Desactualizado: este boletín caducó 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Dangerous avalanche conditions exist. Triggering a very large avalanche 2-3 feet deep is possible in steep terrain above 8500’ that could travel far across the slope or above you. Triggering a large avalanche in wet snow on steep slopes is likely below 8500’.  Natural avalanches remain possible. New snow and wind today will increase the likelihood of triggering an avalanche. Be conservative with decision-making around slopes steeper than 30°.

Problemas de aludes

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Possible
    Tamaño
    1.5–3

    Triggering a large avalanche big enough to bury you is likely on steep, rocky, convex or wind-loaded slopes over 35°.  In areas of the terrain without those characteristics, the likelihood is less, trending more towards possible instead of likely. 2-3 feet of snow that fell this week sits on a variety of weak layers that were covered on January 31st. This 1/31 weak layer is widespread and consists of facets, crusts, wind board, and surface hoar. Avalanches failing on the 1/31 interface could travel far distances (including above you) due to the widespread distribution and continuous nature of the overlying slab. Managing this problem will be difficult because signs of instability, such as collapsing, cracking, or recent avalanches in the last 48 hours may not be present. Many slopes may appear stable until larger triggers or hitting the thin spot produces large avalanches. Choose conservative, lower-angle terrain to manage the dangerous high-consequence avalanche conditions. 

    Weak snow near the base of the snowpack lurks 3-6 feet below the surface. Loading from the recent storm snow is stressing these weak layers in locations that contain a shallower snowpack, such as the Wyoming Range. Avalanches involving these layers could occur with a significant trigger, such as a large avalanche triggered at the 1/31 interface. Keep these layers on your radar if traveling in shallow parts of the forecast zone.

    (2/3/2025)

    A large skier triggered avalanche on a NE facing slope at 9,400' south of JHMR. It likely failed on the new/old interface that was buried on 1/31. 7 skiers were caught and carried. All members of the party survived the incident.

    Photo: Bridger-Teton Avalanche Center

  • Loose Wet

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2

    Triggering wet loose avalanches large enough to bury a person is likely on steep terrain over 35° below 8500’. Unseasonably warm temperatures for the last 36 hours, combined with rain on snow several days ago, have destabilized the snowpack up to middle elevations. Temperatures have remained above freezing in many locations since Monday afternoon. Yesterday, wet avalanches blocked the road in the Snake and Hoback River canyons. Finding wet snow or sinking above your boot are clear signs of unstable conditions. Be aware that these avalanches can start small but entrain larger amounts of snow on sizable slopes or smaller features like couloirs, creeks, or gullies. Be very conservative around terrain traps.

    (2/3/2025)

    Natural wet loose avalanches large enough to bury a person observed recently. 

    Photo: Alex Drinkard

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–1.5

    4-8 inches of snow is expected to fall by 5 pm this evening in the Snake River Range. SW winds will shift to westerly and gust to 50 mph. If this forecast holds true, expect sensitive wind slabs up to a foot thick to form on lee aspects at middle and upper elevations.  Watch for shooting cracks, collapsing, and drifting around cliffs, gullies, and areas exposed to the wind. While these slabs will be small, they could knock you off you feet and have the potential to step down to the 1/31 interface. Ride in sheltered terrain to avoid this problem.

    (2/4/2025)

    A natural wind slab avalanche from the SE ridge of Smoky Hollow Peak. NE aspect 8800'. 

    Photo: Bridger-Teton Avalanche Center

Avalanche Discussion

The snowpack has gone through a lot of rapid change since Jan 31st, causing unstable snow in the top portion of the snowpack. Prior to the recent storms, dry conditions formed widespread weak layers of facets across most aspects and elevations. These weak layers are now buried by dense slabs and capable of producing destructive avalanches. Up to 3” of snow water equivalent (weight of the snow) has fallen in the Snake River Range on a widespread weak interface. Above-freezing temperatures over the last 36 hours in many locations have increased the likelihood of triggering large dry or wet snow avalanches depending on the elevation. More snow and wind today will continue to stress the snowpack.

As we give the snowpack time to adjust, be conservative around avalanche terrain. It’s a good time to go back to an assessment mindset and start digging in the snow to see what and where the latest persistent weak layer (1/31) is up to. Please continue to send in your observations, thanks!

Snow Totals since 1/31: Up to 24” / 3” SWE (snow water equivalent)

Regiones cubiertas