Bollettino valanghe

East Slopes North

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

In sintesi

Recent snowfall and strong E winds formed reactive slabs that you can still trigger on atypical aspects. Avalanches will be easier to trigger in areas that received more snow and where they overly a sun crust. Rollerballs will be precursors to small wet loose avalanches on the southern half of the compass.

Problemi valanghivi

  • Wind Slabs

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

    Around 3" of snow fell around Washington Pass with 0.16" of water equivalent on Monday night; significantly less or no snow fell at lower elevations east of the Pass. E Winds ramped up into the strong range (34 mph, gusting 50). Information in this zone is limited right now, but we suspect that winds drifted fresh snow and pre-existing dry snow on shaded aspects to form generally small, reactive slabs near and above treeline. We expect isolated large slabs at upper elevations near ridgelines. Slabs formed on atypical aspects focusing on the W half of the dial. Winds likely stripped E-facing aspects down to crusts or old snow interfaces. Sharp, fresh cornices above atypical aspects may alternate with older larger cornices that have built up above N and W-facing aspects most of the season. The slopes below these fresher cornices were recently wind loaded and may still be reactive. Cracking snow surfaces, punchy snow, or settlement as you travel also provide warning signs that you're entering wind-loaded areas.  Use your pole or a probe to assess the depth of recent snow above a crust or old snow interface. Become increasingly alert as you find higher average amounts. And if the depth increases locally, you're in a wind-loaded location. Wind slabs will be more stubborn by Wednesday, but you could still trigger one. Steer around wind-loaded slopes steeper than 35 degrees where you expect drifts 6" or deeper and choose more conservative terrain if you're finding more widespread signs of instability including recent avalanches.

    Example: If you start seeing signs such as cracking and little wind-drifted slabs sliding out - shift to a more conservative plan and steer around wind-loaded slopes. 

    Photo: Josh Hirshberg

  • Loose Wet

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

    Light winds, mostly sunny skies, and mild temperatures will conspire to destabilize any recent snow that wasn't wind-hammered on Tuesday. If it feels hot out, it will affect the snow too. In areas with recent snow ankle-deep or greater, watch for rollerballs and shift to shaded aspects, reducing your exposure to the snow that might shed off rocks or cliffs from above. Shallow wet loose avalanches may run quickly and farther than you expect on top of the crust.

     

    Example: Rollerballs and Wet Loose avalanches on a steep sunny slope. Note how they originate at a point near rocks and trees.

    Photo: Rachel Gronvold

Avalanche Discussion

Isolated cornices may also shed in Wednesday's spring-like weather. These cornices could trigger wind slabs on the slopes below. Give larger cornices a wide berth as you travel along ridges and on the slopes below.

Below any recent snow, lower elevations and the southern half of the compass likely have a crust just below the surface. 

Regioni coperte