Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

On Saturday, you're more likely to trigger an avalanche in wind-deposited snow. Look for fresh drifts or firm, hollow-feeling snow near ridgelines, convex slopes, or rocky features. Buried weak layers may wake up this weekend with additional loading, so make travel plans that minimize your exposure to large open slopes.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–2

    Due to a flip-flopping wind direction, you may find wind slabs on various aspects on Saturday. Fierce east winds on Wednesday and Thursday resulted in what are now, older, firmer, and potentially larger slabs. Meanwhile, shallower and softer slabs may have formed as the wind switched westerly on Friday and Saturday. Any of these could overlay soft, weak snow from earlier this week, allowing them to fail easily. Or they could sit on a subtle melt-freeze crust on slopes that typically receive direct sunshine, giving them a good sliding surface.

    It sounds complicated, but your management is relatively simple. Use visual clues such as textured surfaces, fresh cornices, or pillow-like drifts to identify wind-loaded features to avoid. Regardless of direction, the wind tends to deposit snow on leeward ridgelines, convex rollovers, the base of rocks/cliffs, or the sides of gullies/chutes. These are the most likely locations to encounter slabs on Saturday. 

    (2/12/2025)

    Natural wind slab avalanches were observed on Wednesday in the Alpental Valley. These slabs formed and failed without additional snowfall, only wind.

    Photo: Jonathon Spitzer

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2

    Our persistent weak layers should get tested this weekend as we incrementally load them through snow showers and wind. They've already survived an intense east wind event without any reported persistent avalanches. But the big shot of water is in store for Saturday night/Sunday. It remains to be seen if this storm will be enough to wake these layers up and produce avalanches. In the meantime, your best mitigation tool is still avoidance of large open slopes, especially if they're wind-loaded.  Discuss the consequences of a slide with your partners if you are considering non-wind-loaded steeps on the shaded half of the compass. Your default should be to choose simpler, smaller, and lower-angle terrain. 

    (2/2/2025)

    This avalanche released after a audible whumpf. The slide failed on facets over a crust and released the entire width of the feature. NE, 3700ft

    Photo: Summit at Snoqualmie Professional Patrol

Avalanche Discussion

Friday was reasonably quiet at Snoqualmie Pass, with no new avalanches reported. The east winds finally died down, and we experienced a bit of a lull before westerly winds slowly worked their way into the zone in the late afternoon hours. Temperatures started to moderate, a welcome change for many backcountry travelers after a week of bitterly cold conditions. Those east winds were responsible for natural and human-triggered avalanches, shooting cracks, and rapid loading on Wednesday and Thursday. The snow surface is now variable, with a mix of wind-affected snow, sun-crust, and well-settled powder. 

As mentioned in the persistent slab problem, this weekend may put our buried weak layers to the test. The January Drought Layer (JDL) and 1/10 complex are a few feet below the surface and have been dormant for roughly the past week. Snowpack tests and investigations by NWAC forecasters and avalanche professionals indicate that these layers have not healed much during this cold period. They are likely awaiting the right amount of load to start tipping the scales and wake up.  On Thursday, backcountry travelers noted a whumpfing collapse just east of The Pass proper during a period of significant wind transport. Was this the initial wake-up call? We're not going there yet, but as the snow stacks up Saturday afternoon/evening, we'll be thinking about increasing the likelihood of triggering heading into Sunday. If you hear whumpfing collapses or see widely breaking avalanches, dial your terrain selection way back, and please let us know by submitting an observation.

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