Bollettino valanghe

West Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 7 months ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Overall, avalanche danger is low, but don’t let your guard down in terrain exposed to wind. Avoid steep slopes holding wind-drifted snow. Firm or crusty snow could make travel conditions challenging.

Problemi valanghivi

  • Wind Slabs

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

    Shallow new slabs may form where a few inches of new snow are drifted by moderate winds. Older slabs from the last storm are trending unreactive, but could still pose a hazard on very steep, unsupported slopes such as convex rolls, and on slopes above or adjacent to cliffs and rocky features. Wind slabs are more likely to be triggered where they formed over slick crusts.

    Pay attention to changes in new snow depth and slab stiffness as you gain elevation and change aspects. Active blowing and drifting snow will help identify which slopes are currently loading. Cornices, wind lips, and scoured slopes can help you identify wind-loaded terrain if the wind stops blowing. Test small wind-drifted features to assess reactivity before committing to steep, high-consequence terrain. 

     

    The wind often forms thicker slabs around rocky outcroppings. You're more likely to trigger a wind slab in wind-loaded terrain like this.

    Photo: Oliver Kramer

Avalanche Discussion

West Central landed between West North and Stevens and Snoqualmie Pass in terms of precipitation during the latest storm. Given that it also sits geographically between those zones, this may not be surprising. About 1 inch of wet new snow accumulated at 5000 feet, with slightly higher amounts farther east and at higher elevations. While the latest storm produced minimal snow at mid elevations, expect much more dry snow if you make it into true alpine terrain.

Observers in West North reported 2–4 inches of new snow at 5000 feet, increasing to around 12 inches of dry snow in upper elevation, wind-exposed terrain. A rime or melt-freeze crust was found at the snow surface. Steep southerly slopes at mid elevations produced rollerballs under direct sun, but no wet avalanches were observed. A breakable surface crust was found from the Artist Point elevation (5100 feet) and below. At Stevens and Snoqualmie Pass, surface crusts—often breakable—were the main observation, and there was simply not enough new snow to make for meaningful avalanche danger.

Monday should be a benign day in the mountains, both weather- and avalanche-wise. That said, if snowfall amounts or wind speeds come in slightly higher than forecast, wind slab danger could shift from trivial to legitimate in short order. Pay attention to changing conditions.

Regioni coperte