Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Tue
Alta montaña
2 · Moderado
Límite del bosque
2 · Moderado
Bajo el límite
1 · Débil
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Desactualizado: este boletín caducó 6 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

The volcanoes are driving the avalanche danger in the West South as they continue to receive more snow than areas closer to the crest. Regardless of your location, take a look at the upper snowpack on Monday. If you find that the snow is stiffened by the wind or cohesive in nature, avalanche hazard could be higher and you should default to lower angled terrain.

Problemas de aludes

  • Wind Slabs

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

    There is plenty of low density snow sitting on top of the 12/9 crust available for the wind to blow around, and we have reports of shallow Wind Slabs being built this past weekend. Some of these slabs have already been showing signs of failing on weak snow crystals. Keep these slabs on your radar on Monday where you will most likely find them on lee slopes, at the base of cliffs, or on the sides of gullies. Look around and take note of any blowing snow, textured surfaces, or smooth pillow-like piles of snow to help you determine where Wind Slabs may have developed. If you notice clues of unstable snow such as shooting cracks or whumpfing collapses as you travel, steer around wind-loaded terrain.

    (12/12/2020) Cracking in the snow as you travel is an indication that the snow has slab properties and is unstable.

  • Loose Dry

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

    Low-density snow continues to fall on a stout rain crust and with the right conditions, Dry Loose avalanches could run on Monday. Often called sluffs, Dry Loose avalanches start at a point, then entrain additional snow and fan out as they move downhill. These slides can run quickly and far distances and are capable of sweeping you off your feet. So be aware of where you are in terrain and avoid stopping underneath steep slopes or near terrain traps. Unsupported slopes and terrain features steeper than 35 degrees have a higher likelihood of producing these avalanches.

    (12/12/2020) Dry Loose avalanches were running in steep terrain over the weekend in the Paradise area.

Avalanche Discussion

Last week, warm temperatures followed by a rain event helped to create a stout crust (12/9) throughout the West South. This thick crust is being considered our new ground for the time being and close to a foot of snow can be found sitting on it on the volcanoes. Other areas of the zone contain far less snow on the crust, resulting in locally lower avalanche hazard. Regardless of depth,  the snow on top of the crust has remained mostly light and fluffy without much cohesion, except for in specific areas where the wind was able to drift the snow into stiffer slabs. This light and fluffy snow contains some weak snow crystals that we are watching as we continue to increase the load over the next few days. Conditions should remain mostly the same on Monday before a larger storm impacts the area heading into Tuesday. However, take note of how the snow feels on Monday. If you find that the snow is no longer powdery but is more cohesive, the possibility of avalanches is increasing and you may be dealing with a Storm Slab problem and you should default to slopes lower than 35 degrees. Don’t get caught off guard as we move through the different waves of storms this week, the hazard will be increasing at some point.

Recent weather wreaked havoc on the snow in the West South. Firm surfaces abound under the recent fresh snow and many previously buried obstacles have recently reemerged. You’ll need to navigate around numerous open creeks, downed logs, and areas of thin coverage. New snow will help, but realize that these obstacles now may be shallowly buried until we have a few more storms come through. Be cautious and give yourself extra time to manage these variable travel conditions.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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