Bollettino valanghe

Stevens Pass

Northwest Avalanche Center
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Pericolo valanghe

Wed
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
2 · Moderato
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Non aggiornato — questo bollettino è scaduto 6 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Recent snow rests over weak layers in the upper snowpack, and you could easily trigger avalanches on steep slopes. Where winds drifted snow deeper, avalanches could be much larger and break widely across terrain. A conservative mindset and seeking out low-angle, sheltered terrain is the best way to manage the current danger. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Likely
    Dimensione
    1–2

    7-10" of snow fell over weak faceted snow and buried surface hoar. On Monday, observers reported collapsing and both natural and triggered avalanches in new and old snow layers. Southern aspects showed more alarming signs of persistent slabs, including natural and remotely triggered avalanches.  But signs of instability were notable on all aspects.

    Wind-loaded slopes will be particularly dangerous as avalanches may break widely across terrain features or be triggered remotely. You'll want to steer clear of steep lee slopes near ridgelines, where these avalanches are likely to be much larger. In sheltered terrain, avalanches may seem like your average storm slab, but the weak snowpack structure will prevent stability from improving as quickly as you may be used to.

    Long shooting cracks, whumping collapses, or natural avalanches are key indicators of dangerous avalanche conditions. Small, steep test slopes or convex features can help gauge the reactivity of the upper snowpack. But given snowpack variability, be cautious about extrapolating your results too broadly.  Instead, seek out low-angle terrain protected from the wind while we attempt to reduce uncertainty around these tricky, persistent weak layers.

    (2/21/2026)

    An unintentionally triggered, widely propagating avalanche from 2/21. N, 5500ft.  Its unconfirmed, but this slide may have failed on older persistent grains. 

    Photo: NWAC

Avalanche Discussion

The weather will be mild on Tuesday, with cloudy skies, light winds, and a chance of scattered showers. Despite insignificant weather inputs, these persistent weak layers in the snowpack will prevent avalanche conditions from improving much. 

The 2/13 interface is now buried 8-15" deep, and the 2/8 crust is down 15-20". Avalanche activity on Monday suggests that southern aspects may be more reactive than northern aspects. But the weak structure exists on all aspects around the compass.  There were no reports of widely propagating avalanches on Monday, but widespread small natural slides near Jove Peak and a remotely triggered avalanche during avalanche mitigation work at Stevens Pass are all warning signs of a persistent avalanche problem.  These observations were all from southerly aspects. An NWAC forecaster found test slopes were more stubborn on north- and east-facing aspects, but despite the stubborn tests, experienced many collapses in a sheltered north-facing meadow. Avalanches were primarily failing in the recent storm snow and at, or slightly above, the 2/8 crust in a layer of weak faceted snow. 

 About 10-14" below the surface, you'll find a more stout, thicker crust that resulted from warm temperatures and rain in late January and early February. Upper elevations will likely have a greater separation between crusts, with potentially more weak snow between them. But we have limited information from upper elevations, above 6,000ft. If you travel there, we'd love to have your observations!

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