Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Friday should be the proverbial calm before the storm. While you may push some heavy wet snow, or find a random wind-loaded pocket, the hazard will mainly stem from the unlikely but dire potential for an isolated very large avalanche. You’re most likely to encounter one of these big slides in rocky complex terrain. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    1.5–2.5

    It’s hard to imagine this problem suddenly waking up and producing big avalanches on Friday. However, the layers are still there and largely unchanged. It would probably take a big trigger like a small avalanche, cornice, or similar. While these slides could happen on about any aspect, we think they would be more likely in shaded terrain where the weak layers are better developed. 

    Predicting whether any particular slope could slide would be a magic trick. If you want to fully avoid this issue, you’d have to stay off all large steep open slopes. If you’re going to step into steeper terrain weigh the odds in your favor by choosing simple planar slopes with nice clean runouts. Startzones full of rocks and rollovers, provide too many potential trigger points. 

    While there are several layers of concern, the most recent activity Tuesday was primarily on the 2/13 interface. Several natural D2 and one D3 avalanches occurred. 

    (2/18/2025)

    This very large natural avalanche released Tuesday afternoon. on the backside of Chair Peak. It's uncertain exactly which of the older snow layers failed in this slide. WSW, 5400ft, SS-N-D3-R2-O

    Photo: Zack Novak

Avalanche Discussion

Friday is shaping up to be pretty quiet weather wise. Mild temperatures, light winds, and generally minimal precipitation should help the upper snowpack gain strength. Mostly clear skies Tuesday night might even allow the surface to freeze (and form a new crust). All this should help heal recent wind slabs and inter-storm layers (2/18). A little precipitation late in the day won’t do much to increase the hazard. 

Just because there aren’t other avalanche problems doesn’t mean you can trigger a slide. We think these other potential avalanches would be very isolated and small. If you head to the tops of the highest peaks you could find a wind loaded pocket. It would probably take a very steep or unsupported slope to get it to move. Similarly, you might push heavy wet snow into a loose slide in very steep terrain, but they won’t likely travel far or entrain much on their way down. 

There are lots of layers in the upper snowpack. Here’s a quick summary. 

  • 2/13: S aspects: often a sun crust with weak snow just above, N aspects: rimed snow grains and/or surface hoar
  • January Drought Layer (JDL): W-N-E aspects: small facets often with a thin crust. 
  • 1/10 Complex: W-N-E aspects, a thicker layer of alternating larger facets and weak crusts. 

A big change is on the way as a series of very wet and warm storms take aim at the PNW. This isn’t a weekend to go snow camping. Expect the avalanche danger to rise significantly Saturday night.

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