Bollettino valanghe

East Slopes North

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 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You might find significantly wind affected snow, including wind packed and dense slabs in many areas from the strong northeasterlies overnight. Slabs near and above treeline could run on a recently buried crust or on less dense snow. Look for clues such as textured surfaces, hollow sounding snow, and steer around steep slopes if you find shooting cracks.

Problemi valanghivi

  • Wind Slabs

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

    A few inches of new snow may add to some of the recently formed slabs at the highest elevations of the zone. Any triggered slabs are likely to be shallow, but theres also a chance that avalanches break deeper, on a layer of buried surface hoar from early January. Be especially cautious near ridges, beneath large cliffs, and on open steep slopes, that could serve as likely trigger points. You can identify slabs through textured surfaces, and thicker snow. With these, look for signs of instability as you travel such as long shooting cracks, and consider using small test slopes to gain more information on how the snow is reacting. If you observe signs of unstable snow, steer around steeper or more consequential features.

    Long shooting cracks with textured, stiff and wind deposited snow like this one are indicators of wind slab instabilities. Photo: Drew Lovell

Avalanche Discussion

Winds were in the moderate to strong range on Saturday, and most areas likely picked up a skiff to a few inches of new snow. Sheltered locations that don't receive direct sun should still hold nice soft conditions on Sunday. On Friday observers reported ski triggering of a couple small to medium sized wind slabs on east facing slopes at the top of steep chute. These likely ran on the recently buried melt freeze crust from the past few days of warm temperatures and sun. Temperatures were very warm this past week, and observers continued to find some wet loose slides, notably a few large ones over the road to Harts Pass.

The snowpack in the eastern edge of the zone is likely more shallow and you may find these weak layers more readily. We've been tracking a layer of buried surface hoar from January 5th. Near Washington Pass, it's around 2.5ft below the snow surface, but likely more shallow further east. January 12 was the last known human triggered slidethat we know of in this zone on this layer, though one was triggered on the 19th on the east side of Stevens Pass. That same day an observation in the far eastern edge of the zone, near Tiffany Mt indicated that triggering avalanches on the January 5 surface hoar were possible. In the lower elevation foothills, warm, and wet conditions have transformed previously weak, low elevation snow into melt forms. 

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