Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Tue
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
2 · Moderato
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In sintesi

Not much has changed over the last few days regarding the weather or snowpack and neither have the travel considerations.  Continue to avoid hanging out in areas where large glide avalanches can slide off steep smooth slopes with little warning.  Small wet loose avalanches are still possible on steep slopes where you find punchy and wet snow. 

Problemi valanghivi

  • Glide Cracks

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Unlikely
    Dimensione
    1.5–2.5

    Alpental pro-patrol triggered a large glide avalanche off a steep rocky face during avalanche mitigation Sunday.  Temperatures will stay well above freezing Sunday night at mid and upper elevations before a slow cooling trend takes hold on Monday.  Observers have reported crevasse-style glide cracks on nearly every slope over the last few days.  Glide avalanches are hard to predict and can often occur days after the heaviest rain or warmest temperatures.  You aren’t likely to trigger one but they can fail naturally with little warning. Fortunately, these types of avalanches need very specific terrain. Look for very steep rocky slopes with glide cracks and choose routes that reduce the amount of time you're exposed to this overhead hazard.  

    The same can be said for sagging cornices along ridgelines.  You don’t want to be positioned below if these massive blocks of snow release. 

    (1/9/2022)

    A natural Glide avalanche occurred within the Alpental Ski Resort on the night of 1/7. This slide contained the entire season's snowpack as evident by the exposed rock.

    Photo: Alpental Pro Patrol

  • Loose Wet

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

    We'll have one more day of mild temperatures and high freezing levels to end the holiday weekend.  Increasing ridgeline winds and variable cloud cover may limit where snow surfaces soften during the day versus the last few days in this pattern.  Pay attention to the snow surface as you change elevation and aspects.  If you sink in past your ankle or you find very wet and punchy snow, it’s time to seek out lower angle or firmer slopes. Most loose wet avalanches are likely to remain small but use care around terrain traps that would amplify the consequences of a small slide.  In isolated areas where the surface crust breaks down completely, they could entrain additional snow and grow large enough to hurt you.  Steep southerly aspects at mid-elevations are the most suspect Monday. 

    (1/13/2022)

    Nope, this isn't a snowpit. The wet surface snow is weak and unsupportable. If you find the surface crust breaking down, anticipate an increase in the wet potential for wet avalanches. 

    Photo: Andy Harrington

Avalanche Discussion

Variable surface conditions exist throughout the Snoqualmie zone.  Observers reported firm boot and ski supportable surface conditions at lower elevations and shadier aspects Sunday that at times made for difficult travel conditions on steeper slopes.  As we head into Monday, variable cloud cover and temperatures well above freezing at mid and upper slopes makes it difficult to predict the extent of the overnight refreeze.  Regardless, glide avalanches remain a low-likelihood, high consequence problem that should inform your travel routes until we completely exit this pattern. 

Major avalanche cycles occurred Jan 6-7 and Jan 11-12,  and thoroughly tested the snowpack with evidence of large and very large avalanches visible throughout the landscape from these cycles. Below the surface alternating layers of firm crusts, weak wet snow, and strong rounded grains exist. At the moment we aren’t tracking any layers of concern in the upper snowpack. 

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