Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Sun
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

The most likely location for you to trigger an avalanche will be in wind-loaded terrain on Saturday. Be sure to investigate the bond to the underlying crust and use plenty of small slopes to gauge how the new snow reacts to your weight. When in doubt, avoid slopes over 35 degrees.

Problemas de aludes

  • Wind Slabs

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

    The wind has been ripping in the West South zone. Larger drifts likely formed on leeward slopes near ridgelines, convexities, or rocky features such as the base of cliffs and sides of gullies. While a poor bond at the new/old interface could result in avalanches on any slope over 35 degrees, focus on wind-loaded areas where slabs should be larger and more consequential. Collect plenty of information by using small test slopes and hand pits to help identify a poor bond and thus, avalanche likelihood. Shooting cracks or new avalanches are red flags that the snowpack is unhappy and needs time to adjust.

    (1/3/2025)

    A human-triggered avalanche in wind affected terrain near White Pass last week. Similar avalanches could occur at upper elevations on Saturday.

Avalanche Discussion

The snow totals from this storm may not blow you away, but the wind might. Gusts over 100 mph were recorded at Camp Muir for several hours on Friday. Down at White Pass, much of the ski area was closed due to the ferocious winds. In our sister volcano zone, Mt. Hood, avalanche professionals observed slabs as thick as 2 feet deep, while other areas were scoured down to the previous crust. Crystal Mountain Pro Patrol reported 6" wind slabs forming in leeward terrain near ridgelines. 

Add it all up and we have plenty of evidence of wind slab development throughout the zone. The question mark revolves around sheltered terrain and the bond to the underlying crust. Prior to the storm, weak snow such as near-surface facets and surface hoar were observed on top of a firm surface crust. On Friday, Crystal Mountain Pro Patrol and White Pass Pro Patrol both indicated that the bond was initially favorable in their locations, which is promising. Our hunch is that you'll easily trigger avalanches on steep, unsupported, or wind-loaded slopes. Their size will depend on the amount of new snow in your location and exposure to wind. They could be loose or slabs and their moisture content will likely change with elevation. If those weak grains come into play, avalanches could break widely or wrap terrain features.

Prior to this storm, travel conditions were very challenging due to breakable crust, icy slopes, frozen tree bombs, and piles of avalanche debris. The new snow will help, but many of these hazards are now only a few inches below the surface, making them more difficult to spot.

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