Bollettino valanghe

East Slopes North

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
3 · Marcato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
Non aggiornato — questo bollettino è scaduto 5 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

 You can still trigger avalanches where recent snow has been drifted by the wind at upper elevations. Use extra caution around any steep drifted slopes. Expect an increase in avalanche danger with a potent storm on Thursday

Problemi valanghivi

  • Wind Slabs

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

    Steer around wind-loaded slopes 35 degrees and steeper at upper elevations where you could trigger avalanches big enough to bury you. Avalanches will be more likely and bigger above treeline. Keep your distance from thick pillows of snow or wind features. Look for signs of the danger such as blowing snow, recent slab avalanches, shooting cracks, or whumphing collapses. 

    Example storm slab from last week.

    Photo: Stephen Semanski

Avalanche Discussion

On Tuesday, observers on the eastern end of the Washington Pass/Hwy 2 corridor reported a thin sun crust forming on steep sunny slopes. They also found sudden test results (CTH SC) at the Solstice crust, about 2 feet below the surface. New snow totals on Monday were about 9" in the Sage Hills and  18" closer to the top of Washington Pass. On Monday observers reported significant blowing snow at ridgetops near Cutthroat Creek, Liberty Bell, and Delancey ridge areas.

A potent storm will arrive on Thursday and could test any existing weak layer. Cold temperatures in the last week of December created weak and faceted surfaces (see video below for an example from the East Central zone). Interfaces buried on December 29th and January 2nd are within the top 2-3 feet of the snowpack near the Cascade Crest and shallower further east. The interface that was buried around the Solstice is about 2-4 feet below the surface and continues to show the potential for propagation (a critical component in avalanche mechanics). Observers reported finding surface hoar as well as a thin sun crust on steeper S-SW slopes at this interface. While it's uncertain, there's potential for these weak layers to reach their tipping point during the coming storm.  

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