Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
2 · Moderato
Limite del bosco
2 · Moderato
Sotto il limite
1 · Debole
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Non aggiornato — questo bollettino è scaduto 4 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

Sunshine and warm temperatures will make Saturday quite inviting up at the Pass. You’ll need to navigate around natural wet avalanches on sunny slopes and older slab issues in steep rocky terrain. In both cases consider the consequences of a small slide carrying you into a creek, over a cliff, or down a chute.

Problemi valanghivi

  • Wind Slabs

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

    While much less obvious, you may still find lingering slab issues that formed over the past week. These slides could break on some of the inter-storm layers above the 2/3 crust/interface. You’re most likely to trigger a slab in very steep, unsupported, and wind-loaded terrain. 

    Before you commit to more complex slopes, look for subtle signs of wind loading like drifts and cornices that indicate these slopes were loaded by the recent storms. In some cases, a few inches of soft snow may hide obvious wind slab clues from your view.

    (2/9/2023)

    A small wind slab in a classic location, below a cornice on a steep rocky slope. 

    Photo: Andy Harrington

  • Loose Wet

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

    With plenty of sunshine and warming temperatures, loose wet slides will be the most in-your-face issue of the day. Fortunately, it should be easy to anticipate and manage. When you see snow shedding from trees/rocks or find new rollerballs, that means the snow surface is becoming wet and unstable. Loose wet slides will likely follow. 

    So, when you see these telltale signs, start paying attention to the terrain above you. You can avoid this problem by seeking out shade aspects. If you need to travel under sunny avalanche terrain, reduce your risk by only exposing one member of your team at a time, spreading out, and avoiding areas above high-consequence runouts.

    (2/1/2023)

    Example: You could see natural slides like this during Saturday's sunny  weather. 

    Photo: Andy Harrington

Avalanche Discussion

We’re sort of in a transition day Saturday at the Pass, where lingering storm issues continue to decline, but sunny weather will help develop new avalanche hazards. While these can be good days to head into higher terrain and seek out bigger objectives, often those are the same areas we’re concerned about avalanches. 

Observations from the Pass on Friday highlighted two important notes. 1. Snowpack tests continue to show recent storm snow layers are healing. 2. In some very specific locations lingering wind slabs still exist. 

Friday we added a few more inches to the week’s storm totals. You’ll probably find that the new snow increases dramatically with elevation. In fact, often we’ve said you’re dealing with two snowpacks, the one below 4500ft and the one above. That’s still mostly the case. If you travel above this line, consider the entire upper snowpack above the 2/3 interface. At upper elevations that could be 2-3ft deep (60-90cm). At lower elevations, less new snow will significantly limit the avalanche hazard. On more southerly slopes new surface crusts have been reported.

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