Boletín de aludes

Galena Summit & Eastern Mtns

Sawtooth Avalanche Center
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Peligro de aludes

Wed
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 4 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Human-triggered avalanches involving dense, hard snow sitting on weak layers beneath are possible in rocky, wind-affected, alpine terrain. Avoiding this type of terrain will reduce your risk of triggering a large avalanche today. Look for areas where the wind has built a fresh batch of smaller drifts and slabs out of the new snow. Even small slides that knock you off your feet or machine can carry high consequences in rocky, treed terrain.

The likelihood of triggering avalanches will increase through the morning hours as the storm brings new snow and strong winds. The White Cloud Mountains are expected to receive the most snow and conditions will be the most dangerous there.

Problemas de aludes

  • Wind Slabs

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

    Small, thin wind slabs are building on a variety of weak surfaces that developed over the past several weeks. Though not large enough to bury you, these slabs can knock you off your feet and carry you downslope. Look for them near ridgelines in terrain exposed to the wind. Strong winds can build slabs in unusual locations, expect to find slabs extending down into most middle elevation terrain and some lower elevation terrain. Dune-shaped drifts and textures on the snow surface like waves and ripples are signs that the wind has been at work, as are fresh cornices along ridgelines.

    More snow is falling in the northern portion of this zone, from Galena Summit north into the White Clouds. Fresh slabs will be larger and more reactive here.

  • Persistent Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Unlikely
    Tamaño
    1.5–2.5

    Dense, 1-4 foot thick slabs of snow rest on top of layers of weak, sugary snow here. You're most likely to find a spot where you could trigger a slide involving these hard slabs in rocky, alpine, upper elevation terrain where the wind has scoured the snowpack, creating thicker and thinner areas. Here, these weak layers are closer to the surface and impacting them with your weight remains a possibility. 

    Fortunately, avoiding this problem is fairly straightforward. You can dramatically reduce your risk of triggering a large avalanche today by avoiding rocky, wind-affected alpine terrain steeper than about 35 degrees. Unfortunately, there is quite a bit of terrain that looks like this in the mountains along the eastern rim of this zone—from the White Clouds down south through the Boulders and into the Pioneers. 

Avalanche Discussion

There is a good deal of uncertainty with today's Forecast. Thus far, the storm has been a significant underachiever—more of an atmospheric rivulet than an atmospheric river. Snow totals have been on the light side, but in addition to the persistent slab problem described above there are some storm-related issues to be looking out for today:

Wind slabs: The combination of fresh snow and strong winds is building sensitive wind slabs. Strong winds build slabs in unusual locations. I expect to see slabs at most elevations, though these will be largest and most reactive in exposed middle and upper elevation terrain. Slabs may be building even at lower elevations. These are likely to be smaller and your biggest concern with them involves being pushed into terrain traps like creek bottoms and dense trees. Typical locations for low elevation wind slabs in this zone are in the foothills of the Boulder Mountains and on the slopes on the east side of Highway 75 in the foothills of the White Clouds. Slabs are building on a variety of weak snow surfaces that developed over the past weeks. Avalanches that fail on these weak layers will break wider and may be more sensitive than you might expect a "simple" wind slab to be.

Loose snow: If you are finding soft, sheltered snow in very steep terrain (approaching 40 degrees) you'll be able to trigger loose snow avalanches today. These will involve both the new snow and the weak, faceted snow described above. Today's cold front should keep things cooler than yesterday, but if you're playing on slopes that face the sun and finding moist/wet snow you'll be well served to think about triggering a small wet loose avalanche.

Deeper in the snowpack you'll find some ugly weak snow sitting underneath very dense slabs. Triggering a large involving this snow is unlikely, but the outside possibility continues to drive my terrain selection in this zone. Fortunately, avoiding this problem is fairly straightforward. You can dramatically reduce your risk of triggering a large avalanche today by avoiding rocky, wind-affected alpine terrain steeper than about 35 degrees. Unfortunately, there is quite a bit of terrain that looks like this in the mountains along the eastern rim of this zone—from the White Clouds down south through the Boulders and into the Pioneers. 

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