Boletín de aludes

Mount Shasta

Mount Shasta Avalanche Center
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Peligro de aludes

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

Lo esencial

Additional snow and wind continue to elevate the avalanche danger. You could trigger an avalanche large enough to bury or kill you on wind loaded slopes near and above the treeline. Watch for snow surfaces that appear denser and stay away from steep slopes greater than 30° where blowing snow is or has been accumulating.

Problemas de aludes

  • Wind Slabs

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

    A consistent stream of precipitation and moderate to strong wind continues to build wind slabs near and above the treeline. You will find the largest and most sensitive wind slabs above the treeline, where snowfall accumulations have been greater, temperatures have stayed below freezing, and there is available snow for transport. The most common aspects that you'll encounter this problem on today will face north, northeast, east,and southeast. Though, with these strong wind speeds and differing local wind directions across the forecast area, you may come across a wind slab in unexpected places such as mid-slope into the leeward side of terrain features (cross-loading) or on westerly aspects.

    You could trigger a wind slab avalanche today large enough to bury or kill someone in your group. 

    So what can you do about it? Avoid traveling on or beneath wind loaded, steep slopes by looking for where the blowing snow is accumulating and feeling for denser snow underfoot.

Avalanche Discussion

Considerable avalanche danger persists above treeline because of days of ongoing precipitation and strong shifting winds. Last night and into this morning, precipitation rates increased, as did the speed of the southwest wind. Today will be peak conditions for triggering a wind slab above treeline before a break in weather tonight and tomorrow will offer the snowpack an opportunity to adjust to its new load. Public observations from Green Butte Ridge along with our findings from across the forecast area, confirm a widespread distribution of wind slabs. 

We're tracking a weak layer 30+ centimeters down from the surface that sits above a melt-freeze crust. This weak layer of decomposing fragments is drier and less dense than the wet, heavy rounds and/or wind-packed snow that rests above it. We often describe this structure as an upside-down snowpack. This is because it is unstable, with a profile of strong, well-bonded snow (slab) above weaker, less-bonded snow. In higher elevations and on steeper terrain, the weight of a rider on this snowpack structure could trigger an avalanche. Travel with caution in the mountains today, especially above the treeline. 

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