Boletín de aludes

Stevens Pass

Northwest 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 2 years ago. Estás viendo condiciones pasadas, no el boletín vigente.

Lo esencial

It's possible you can trigger a lingering storm snow avalanche in the layer that fell over the weekend and is less than a foot deep. Start small, beware of large, convex slopes, and when in doubt, continue to avoid big, steep slopes. Small, shallow wet avalanches may run as temperatures warm up midday or if the sun comes out. 

Problemas de aludes

  • Storm Slabs

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

    Human triggered storm slab avalanches remain possible on Tuesday, although you can expect a continued downward trend in avalanche activity being one day further out from the storm. We didn't receive any reports of human-triggered avalanches on Monday, although one observer reported a natural storm slab avalanche in the Smithbrook area. 

    Avalanches will probably be around 4-10" deep. You're most likely to trigger a slide on steep, convex rolls, and beneath or around cliffs. Avoid these locations on large slopes, or on any steep slopes where terrain traps exist below. When in doubt, avoid all terrain greater than 35°. 

    Slides will be easier to trigger in wind-loaded locations. An avalanche here could be deeper and span wider than non wind-loaded areas. Search for textured or smooth, pillowlike surfaces and avoid these in steep areas. 

    Example photo: A soft slab avalanche, similar to what might still occur with a human trigger on Tuesday. 

    Photo: Irene Henninger

  • Loose Wet

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

    A round of wet loose avalanches occurred on Monday. Temperatures are expected to be similar on Tuesday, and we may see another round of wet avalanche activity.

    Monitor snow surfaces. Due to moistened surfaces on Monday the day may start with a thin, soft crust to over 5000ft.  If snow starts getting wet, and if you see rollerballs or any slides, avoid traveling on similar steep terrain or lower angle terrain below.

    Even if natural avalanches don't happen, you might be able to trigger a slide on a steep slope. In the morning there could be low clouds which may cause "greenhousing", where all aspects get moist. Potential afternoon sun breaks may mean that avalanche activity may be limited to steep slopes facing the sun, at least during that time period. 

    (2/17/2025)

    Natural wet loose avalanches ran during the day in the Smithbrook area on Monday. Similar activity might occur on Tuesday. 

    Photo: Roman Pavenko

Avalanche Discussion

The storm didn't produce quite as much snow as we expected, with totals of about 6-10 inches. Nevertheless, loose dry, then storm slab avalanches occurred, before a warming resulted in wet loose avalanches as well. Stevens Pass Patrol triggered several avalanches that were 4-8" deep in the new storm snow with explosives on Monday morning. They triggered one avalanche with a large explosive charge on a steep, unsupported convex roll that failed deeper, possibly down to the January Drought Layer (media gallery).  

Aside from the one triggered with a large explosive round at the ski area, there was no reported activity on our buried weak layers of concern, the January Drought Layer and underlying 1/10 layer. Uncertainty surrounds when (or if) avalanches will start occurring on these layers. They exist roughly 2-3 feet below the surface, and we no longer seem to be getting results on snowpack tests. When these layers were first buried, there were numerous reports of whumpfing collapses and shooting cracks but no reports of associated avalanches in the zone. 

I traveled to the Skyline area Monday morning and found light, dry snow in the morning, with a little evidence of rollerballs from the previous day's warming. Pit tests on north and south aspects both showed subtle instabilities in the new storm layers, about 4 inches and 10 inches deep. No other results further down were noted. I didn't see any new avalanches but left midday before the bulk of the wet activity began. A rider at Smithbrook noted moist snow to over 5200ft and natural wet loose avalanches in the afternoon, with natural shallow slab avalanches also visible. Tuesday will be a relatively calm, mild day before more snow comes on Wednesday. 

If you get out in the backcountry, please share what you see by submitting an observation HERE or on the Avy App. 

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