Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
View on map

Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A highly variable and potentially weak snowpack combined with significant recent storm snow will make for dangerous avalanche conditions. It will be nearly impossible to tell how any one slope may react. Steer clear of steep open slopes, particularly on shadier aspects.

Avalanche problems

  • Storm Slabs

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

    These aren’t your run of the mill PNW storm slabs. You’ll need a different much more conservative approach. Quick hand pits, uptrack tests, and small slopes could leave you feeling overconfident in conditions.  

    There are subtle layers within the new snow that may fail and create shallow avalanches. These will be most common in wind loaded terrain, on very steep slopes, or near convex rollovers at middle and upper elevations. These slides should be smaller and easier to manage. 

    The real worry is for a slab to break at the base of the recent storm snow (12-24 in). These avalanches could fail on weak facets and slide on a crust below. Recent audible whumpfs and significant snowpack test results indicate these deeper avalanches are possible. However, an immense amount of variability in the old surface makes figuring out exactly which slopes to avoid, nearly impossible. Even tracks on a slope don’t mean it’s safe. Dial it back and give the snowpack time to adjust to the new load.

    A skier triggered slab avalanche from Saturday. SS-AS-D1.5

    (2/1/2025)

Avalanche Discussion

One long-time avalanche professional called these conditions, “consistently inconsistent.” That sums it up very well! It sure makes it very tricky to manage this snowpack in the mountains. Don’t run your normal playbook. The variability could easily lull you to sleep. Focus on the information that points towards an unstable snowpack and let it guide you.

Is this a persistent slab problem? Well, there’s certainly a persistent weak layer. Sugary facets and occasionally surface hoar are common at the base of the new snow and beneath crusts in the upper snowpack. An NWAC forecaster triggered a rumbling whumpf on an N aspect at 5200ft Saturday. Other travelers in the zone reported collapses and snowpack tests that propagated across large blocks (ECTP). So far we haven’t confirmed avalanches failing on this layer. That could change. 

The storm is winding down, but cold temperatures and low density snow will continue. This may not allow weak layers to heal as quickly as normal. Observations on Saturday noted several density changes in all the new snow and a smattering of small human triggered soft slab avalanches. As this storm ends cold, expect light fluffy snow on top. You may trigger dry loose avalanches (sluffs) that run quickly, even in the trees. In open terrain, these slides could act as the trigger for larger avalanches. 

At lower elevations, travel has improved, but many observations indicate it’s still scratchy, particularly in the trees. With less snow down low, expect smaller avalanches and slightly less avalanche danger.

Regions covered