Boletín de aludes

Bitterroot

West Central Montana Avalanche Center
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Peligro de aludes

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

Lo esencial

Skiers and riders could trigger small wind slabs at upper elevations today. Look out for shooting cracks and avoid steep slopes with wind-scalloped pillows of drifted snow. Additionally, be prepared to manage dry loose avalanches on steep north slopes with unconsolidated surface snow. 

Problemas de aludes

  • Wind Slabs

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

    Since Friday, 4 to 14 inches of snow fell throughout the region, with moderate winds creating wind slabs at upper elevations. Skiers and riders could trigger these lingering wind slabs today near ridge tops and along the edges of gullies. Any wind slab triggered today would likely be small but could still knock you off your feet and carry you into or over hazards. Stay alert for shooting cracks and wind-scalloped pillows of drifted snow. The best way to manage the hazard is to avoid wind-loaded slopes over 35 degrees. 

  • Loose Dry

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

    Yesterday, low-density surface snow was sluffing easily on steep slopes. Small dry loose avalanches are possible on shaded slopes today where the recent snow is not wind-affected or crusted. Manage dry loose avalanches by getting out of their way and letting them run. These avalanches could push riders into or over terrain traps, especially where they funnel in chutes. 

    Increased cloud cover combined with crusted over south aspects should keep most wet loose avalanches at bay today. However, if the sun shines more than expected, wet loose avalanches could become possible on sunny aspects. Yesterday observers in the Central Bitterroot were able to trigger small wet loose avalanches that slid on slick crusts. If the snow is wet and rollerballs start, it's a sign to move to lower angle slopes or shadier aspects.

Avalanche Discussion

Spring weather returned yesterday, but after a weekend of cold and snowy weather, we still have some dry snow avalanche problems to deal with. The good news is that these avalanche problems are generally small and isolated to the recent snow. 

Snow totals from Friday through Sunday range from 4 to 14 inches, with the Southern Bitterroot receiving the most snow and Seeley Lake receiving the least. The snow fell on slick crusts on south aspects and near surface facets on north aspects. The snow came in with moderate north winds, and in the last few days, observers found reactive wind slabs in all zones near upper elevation ridgelines. These wind slabs are becoming more stubborn to trigger, but the instability is lingering. Be prepared to manage wind slabs and dry loose avalanches if you step out into steeper terrain. These avalanches are small but could still prove consequential around terrain traps. 

We received reports yesterday of a very large avalanche in the Northern Beaverhead Mountains, south of our forecast area. The avalanche was on a north aspect at around 9500 ft. It failed at the ground and created a totally new avalanche path destroying tens of acres of mature timber. It likely failed naturally on Sunday due to new snow and wind loading. 

The snowpack in the Northern Beaverhead Mountains is generally thinner, with a poorer structure and more weak layers than in our forecast area. However, the snowpack in the Southern Bitterroot near Lost Trail Pass shares some of these characteristics. If you are heading out in the Southern Bitterroot or areas further south into Idaho, stay alert for the potential for deeper and more dangerous instabilities. Digging snowpits can help identify problematic buried weak layers. 

Lately, we have been lucky to generally only have to deal with new snow avalanche problems and be able to operate in a spring-like mindset. However, many other areas in the mountain west are still dealing with buried persistent weak layers and have dangerous avalanche conditions. If you travel outside of our region, be prepared to switch gears into a much more mid-winter-like mindset. 

Please let us know what you find out there today by submitting an observation. 

Ski and ride safe.

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