Bulletin d’avalanche

Snoqualmie Pass

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
2 · Modéré
Sous la limite
2 · Modéré
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

Until conditions cool, continue to avoid terrain where glide avalanches can occur.  These avalanches are powerful and hard to predict. Creeks are gushing and the snowpack is thin in parts of the zone so be prepared for atypcial mid-winter travel. 

Problèmes avalancheux

  • Glide Cracks

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    2–3

    Most wet snow avalanches have run their course over the last few days and now human or natural triggered slides are less likely than earlier a few days ago.  However, we know that below the surface water is still moving through the snowpack, leaving the door open for powerful glide avalanches.  Glides are difficult to predict and often occur well after peak rainfall and warmth.  Until we've had an extended cool down,  look for the glide cracks informally known as the "brown frown", and avoid traveling on or below them.  Steer clear of steep open terrain where you still find wet and punchy snow. If you find a firm supportable crust at higher elevations, the wet snow hazard will be lower.  

    Besides glide avalanches, keep an eye out for sagging cornices, or precariously perched blocks of snow to help identify areas where snow may shed during the persistent mild weather. Cornices can fail without warning, possibly triggering slabs or loose avalanches on the slopes below. Give these areas a wide berth as you travel.

    (1/30/2024)

    A glide avalanche on Rockface at Alpental. This frequent flier is a good indicator that water is still making its way through the snowpack. We're not done with wet snow avalanches.

    [E 3900' WS-N-R2-D2-G]

    Photo: Alpental Pro Patrol

Avalanche Discussion

Beginning Thursday night, cooler temperatures will arrive at upper elevations, signaling the beginning of a cooling trend.  Before this, temperatures have been sitting above freezing at lower and mid elevations for almost a week (!). The snowpack absorbed 3" of water over this period, mostly in the form of rain.   

New glide avalanches were reported on Thursday by Alpental pro-patrol.  Observers continued to find evidence of recent wet snow avalanches on Wednesday in the Alpental backcountry along with new creek blowouts. 

Over the weekend, we had a significant wet avalanche cycle as the aforementioned atmospheric river impacted the Pacific Northwest. NWAC forecasters documented slides up to size D3 on Monday morning.  In neighboring zones that received more rainfall over the past few days, very large and destructive avalanches have been more commonplace. Many of these slides involved similar pre-storm layering to the Snoqualmie Pass zone.  

Come prepared - open and gushing creeks, heavy wet snow, runneled surfaces, and avalanche debris now litter the landscape, raising the likelihood that you'll encounter challenging travel conditions. 

Régions couvertes