Bollettino valanghe

Snoqualmie Pass

Northwest Avalanche Center
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Pericolo valanghe

Sun
Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
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In sintesi

A potent storm will impact Snoqualmie Pass this weekend, reminding us it's still winter in the mountains. Heavy snow and strong winds will create dangerous avalanche conditions on slopes over 35 degrees. Avalanches could fail naturally, break in surprising ways, or run far distances on an underlying crust.

Problemi valanghivi

  • Storm Slabs

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

    This will be the strongest storm of the week, delivering several rounds of precipitation and strong winds. You'll need to manage new snow problems wherever you travel on Saturday, but avalanches should be easier to trigger on slopes over 35 degrees. Slabs will be larger as you ascend in elevation or wind-loaded terrain, which could be on any aspect due to a mid-storm wind direction shift. Using uptrack tests, hand pits, or small test slopes can indicate how the new snow is setting up. But to assess the actual hazard, you'll likely need to dig down to the AR crust to get a feel for potential failure points. Depending on your elevation or location, this could be 6 inches to a couple feet below the surface. Keep it simple - avoid slopes over 35 degrees where avalanches are more likely until this storm has passed.

    (3/12/2025) 

    A human-triggered slab avalanche on a steep slope on Chair Peak earlier this week.  Expect a lot of this over the weekend.

     Photo: Olly Cohen

Avalanche Discussion

After a relative lull on Friday, our stormy week will continue into the weekend. This next round should pack more of a punch than we've experienced thus far, increasing avalanche potential and size. We've already had a steady stream of reported avalanches in recent days, including storm slab, wind slab, dry loose, wet loose, and glide. Apart from the glide, all of these have involved recent storm snow and that's the message heading into Saturday. Whatever avalanche problem you want to use to best describe it, you'll need to manage all the storm snow from this week while traveling in the mountains. We now have several interfaces with variable depth over a crust. The wind has created unstable drifts on both sides of ridgelines. In isolated locations, weak snow could exist near the bottom of this week's storm snow, which could be several feet deep by the time Saturday rolls around. This means avalanches could break deeply or in surprising ways. 

Add it all up and it's shaping up to be a dangerous day in the mountains, so you should treat it as such. Dial your terrain selection back, don't be shocked to see natural avalanche activity during or shortly after periods of intense precipitation or wind, and make good assessments before committing to a slope. If there is an extended span of sunshine, be leery of wet avalanches in the new snow.

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