Bollettino valanghe

East Slopes South

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You may not notice any obvious signs of instability, but triggering a large avalanche is still possible on steep, open slopes. You can reduce the odds of being surprised by a large avalanche by avoiding steep open terrain, especially if they appear wind-loaded. Loose snow avalanches may still release in more sheltered terrain or on slopes that face the sun. 

Problemi valanghivi

  • Persistent Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2

    The January Drought Layer remains a concerning weak layer across the East South zone. In general, you can find this crust/facet layer 1-2’ below the surface. This avalanche problem will be more dangerous in locations closer to the cascade crest where more recent snow fell or in areas with recent wind loading. So far, forecasters and observers have found this interface the weakest and most problematic on NW-E aspects across the region. 

    Snowpack cracking and collapsing or whumpfing are clear signs of unstable conditions. However, a lack of these obvious warning signs doesn't mean you're in the clear. Persistent Slabs can release in surprising ways, break wider than expected, and release above or hundreds of feet away from where they are triggered. 

    The best way you can reduce your odds of triggering one of these large avalanches is by avoiding steep terrain greater than 30 degrees. 

    (2/3/2025)

    A skier triggered persistent slab avalanche near White Pass. This slide released over a 100ft wide and 2-3ft deep. WNW, 5600ft SS-ASu-D2-R2-O

  • Wind Slabs

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

    Moderate wind speeds are likely drifting low-density new snow into soft, cohesive slabs along ridgelines and in alpine terrain. Look for these slabs to become thicker and more widespread as you gain elevation into exposed terrain.

    You’ll typically find these wind slabs on the downwind side of ridges, below cornices, near rocks and cliffs, and on terrain rollovers exposed to the wind. Look for blowing snow and surface clues like wind-etched snow, dunes, and pillowy slabs to help you identify where these slabs may lurk.

    These avalanches could step down to the buried weak layers described above. The best way to manage wind slabs during these periods with a persistent slab listed, is to simply avoid wind loaded slopes altogether. Shooting cracks or audible whumphs are signs that you found an unstable slab.

Avalanche Discussion

The persistent slab problem listed may give you less signs of instability, but forecasters confirmed the structure is still present and is still able to propagate across a slope if triggered. You can check out the full observation here. 

We suspect the most concerning places are closer to the Cascade Crest or in wind loaded terrain. Observations continue to report weak snowpack structure across the region, but not every location has the cohesive slab resting over this. The best way to manage this is by increasing your margins and avoiding steep, open slopes on the north side of the compass, especially if you notice obvious over a foot of stiffer snow resting on weak facets. 

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