Bollettino valanghe

East Slopes Central

Northwest Avalanche Center
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Pericolo valanghe

Thu
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 6 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The sun may be out, but you may still be able to trigger a slab avalanche on Wednesday. Identify steep slopes and features with recently drifted snow to avoid.  Watch for signs of instability such as shooting cracks and whumphing collapses. A weak layer of snow may exist between the recently wind transported snow and previous surfaces. 

Problemi valanghivi

  • Wind Slabs

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

    Very strong winds and new snowfall left wind slabs scattered about in pockety distribution. Wind slabs may be triggered by surprise, and may propagate wider than anticipated. A layer of surface hoar was observed in many parts of the zone before the recent storm, so these slabs may continue to be reactive longer than you may think. Expect potentially larger avalanches as you ascend, where slabs may be thicker. If you see shooting cracks or hear whumpfs, dial back your terrain choices and stay off of steep features. This is also a good time to dig lots of quick pits, looking for a thin grey stripe of buried surface hoar.

    Identify recently wind loaded slopes and observe for cracking or whumphing in the snow as you travel. If you do find these signs of instability, avoid the obvious steep, wind loaded slopes, but also take into account cross-loaded and midslope features. Use surface textures and cornice formation as visual clues where slabs may be. Hollow sounding and firm or textured snow are other clues that wind transport has created slabs. 

Avalanche Discussion

We don't have any firsthand reports from the East Central since the storm blew through on 11/30, as such this forecast comes with a fair amount of uncertainty. On Sunday, I found widespread surface hoar in the North Fork of the Teanaway on all aspects above 5000'. Other observers found surface hoar in places like the Chiwaukum Range as well. If preserved, and buried by a cohesive slab, this could create a tricky situation for the next few days. Snowpack height and coverage varies significantly across the area. Areas near the cascade crest have a substantially deeper snowpack than low elevations and further east. 

Look for rollerballs or small loose avalanches in very steep terrain where unconsolidated snow escaped the wind. On steep south facing slopes, the sun may warm the snow enough to create small wet loose slides. In the shade, loose dry avalanches may carry momentum and entrain weakening snow surfaces. 

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

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