Bollettino valanghe

East 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 3 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

A weak storm will bring light snow and southwest wind to the zone Sunday night. You can trigger small slab avalanches where the wind forms fresh drifts of snow just below ridges. Choose lower-angle terrain where you identify stiff, wind-drifted snow.

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–1.5

    Southwest winds should be strong through Sunday night to transport snow, but will taper by Monday morning. Where there's enough snow to form drifts, you could trigger shallow wind slab avalanches on leeward slopes steeper than 35 degrees. 

    You may not see lowing snow will help you identify which aspects are actively being loaded.  Other clues to these avalanches are long shooting cracks or observing stiffer snow as you move higher in terrain.  If you're unsure, stick to lower angle and more sheltered terrain away from ridgelines.

    (2/9/2024)

    You can trigger similar wind slabs on Saturday that will likely break on the recent crust. This small skier-triggered avalanche occurred in the Washington Pass area on Friday.  SE aspect, 7200 ft. 

     

    Photo: Harry Keane

Avalanche Discussion

Up to 4" of snow accumulated near the Cascade Crest, especially in the southern end of the zone in the Salmon LaSac area. The Wenatchee Mountains picked up a trace of snow. Expect another inch or two by Monday morning.

We have limited information from upper elevations across the zone. The forecast team is unsure how the upper elevation snowpack is bonding to the early February crust. So, as you climb into the alpine, ease into the terrain and be ready to make your own assessments.

Across much of the zone, you'll find 3-5" of new snow over the recent crust at mid and upper elevations, with more the higher you go. On Friday, an observer traveled up to 8,000ft in the Stuart Range and found little signs of instability. Observers have been finding surface hoar over the early February crust, including forecasters on Tuesday at Blewett Pass. It was difficult to identify, but the feel of slippery snow over the crust (see photo below). Any new wind slabs that do form could become reactive with potential for buried surface hoar or facets over the crust. Check out another observation from the Wenatchee Mountains where they found collapsing of the new snow on the crust. 

Your avalanche, snowpack, or weather observations are extremely valuable to the forecasters at NWAC. Help create a more accurate avalanche forecast by submitting your observations here. 

 

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