Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Mon
Alta quota
2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

You can trigger small avalanches at upper elevations where the wind has drifted recent snow.  Look out for pillow-like slabs below areas of blowing snow, sharp drifts, and textured surfaces. On Sunday, expect a chance for light snow, cold temperatures, and southerly wind.

Problemi valanghivi

  • Wind Slabs

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

    Strong winds built fresh slabs in the classic places along exposed ridges, at the tops of chutes, and near the base of cliffs. If you find signs of instability, like cracks shooting through the snow or wind drifts that break easily with the weight of a person, stay off of leeward slopes over 35 degrees. Look for visual clues like sharp wind drifts and stiffer snow surfaces. Steer around fresh drifts and stick to lower-angle or wind-sheltered slopes. 

    A warm and windy storm on Friday brought a few inches of snow with strong southwesterly winds. With the warm start to the storm, any wind slabs should only be moderately reactive. If you find any underlying old, weak snow, you may be able to trigger the slabs easily or in surprising ways.

    (12/22/2023)

    Cracks in recently wind transported snow near Harts Pass.

    Photo: Willie Webster

Avalanche Discussion

A storm on Friday brought about 4-5" of new snow and stronger winds to the zone. Observers in the Harts Pass and Willow Creek areas noted significant blowing snow, fresh wind features (6-8" deep), and cracks in the new snow.

This new snow fell on a variety of old surfaces, but two seem more prominent. Surface hoar was seen particularly on shaded aspects. On Wednesday, observers on Rainy Pass found it on the surface as well as buried in the top 8" of the snowpack. In steeper, more southerly terrain, a surface crust likely formed. As you travel, take note of where they survived by using small hand pits.

Similarly, older layers of buried surface hoar and the 12/10 crust (below ~6000ft) may be found slightly deeper in the snowpack. The prominent 12/7 atmospheric rain crust continues to be an excellent snowpack marker for tracking variations in the upper snowpack across the terrain.

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