Boletín de aludes

West Slopes South

Northwest Avalanche Center
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Peligro de aludes

Fri
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
2 · Moderado
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Desactualizado: este boletín caducó 6 months ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

Strong winds will further stress an already dangerous and unstable snowpack. All steep slopes have the potential to avalanche, but areas of wind loading may be extra sensitive and release larger slides. Keep it simple, limit your time on or beneath steep slopes, and lean on lower-angle terrain for travel.

Problemas de aludes

  • Persistent Slabs

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

    Wind-blown snow will be the more obvious problem as you get to the mountains on Thursday, but persistent slab is the scary problem you should be planning for. Any steep slope is suspect. Persistent slab activity is likely to continue on Thursday, with the weight of wind-loaded snow straining weak layers in the snowpack. The 2/13 and 2/7 weak layers are now at least 1.5 feet beneath the surface, but have shown little slowdown in activity. Multiple large natural and explosive-triggered avalanches were reported on Wednesday.

    Overnight into Thursday, strong ridgeline wind will make quick work of redistributing all the recent fresh snow, potentially forming unstable slabs. If triggered, these slabs could step down into the weak layers deeper in the snowpack, producing an even larger avalanche. 

    Manage both of these issues with the same tactics. The mountains have made it clear: these weak layers are dangerous and can produce large avalanches, so you need to stay out of their way. Limit your time traveling on any steep terrain, especially leeward-facing, rocky slopes that could be wind-loaded.

    (2/24/2026)

    A natural, large (D3) persistent slab that released over 800 feet wide in the West South zone. This avalanche failed on the 2/13 buried surface hoar.

    Photo: Crystal Mountain Pro Patrol

Avalanche Discussion

Wednesday brought warmer temperatures and an uptick in wind to the West South zone. A new, thin surface crust has already been reported near Crystal Mountain. Numerous large, natural, and explosive-triggered avalanches were reported on buried weak layers. Our friends at the United States Geological Survey reported many large to very large avalanches over the past three days on the southern volcanoes, with a heavy focus on Mount St. Helens. Observers witnessed the northside of Mount Rainier National Park littered with recent avalanche activity.

The snowpack around the West South currently consists of 6–8 inches of recent, denser snow on top of up to a foot of lower-density snow from last week. Below that are two buried weak layers: the 2/13 and 2/7 interfaces. The 2/13 interface consists of preserved 2–4 mm surface hoar. The 2/7 interface is a combination of surface hoar and facets surrounding a crust. Beneath that crust lies a series of weakened melt forms. Once below this weaker snow, the snowpack becomes strong and supportable to the ground.

Cloud cover on Thursday should be similar to Wednesday, with periods of sunshine and semi-consistent cloud cover. As slopes warm, watch for signs of destabilizing surface snow such as roller balls, small point-release avalanches, or snow shedding off rocks and trees. If it starts to feel warm and sticky, consider moving to shadier, lower-angle slopes.

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