Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Don’t let the relative break in the weather lure you into a false sense of security. Conditions have been touchy and there is a lot of uncertainty about upper elevations. Recent avalanches continue to point toward the snowpack needing time to heal, so stick to conservative terrain and keep an eye on the incoming storm.

Avalanche problems

  • Storm Slabs

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

    You should continue to be leery of slab avalanches on slopes over 30 degrees on Wednesday. We have had near continuous snowfall since Sunday, and strong winds at the start of the storm may have created thicker slabs in wind-prone areas. Digging in the snow with your hand or shovel can help you identify heavy over lighter snow or storm instabilities that could be a point of failure. We expect most avalanches to occur within the recent storm snow above the 1/2 interface, so you can focus your efforts on these layers. Using test slopes, quick hand pits, and uptrack tests as you travel may give you an indication of the bonding of the recent snow and the potential for slab avalanches. Red flag signs of instability such as shooting cracks, whumpfing collapses, or recent avalanches are a great indicator to dial back your terrain selection. When in doubt, avoid slopes over 30 degrees or areas where you are more likely to trigger an avalanche such as convex rollovers, the base of cliffs, or confined chutes and gullies.

    (1/4/2022)

    Soft Slabs 12-14" deep were easily triggered in the storm snow by ski cuts and explosives during Alpental's control work on 1/4/22.

    Photo: Alpental Pro Patrol

Avalanche Discussion

We are just wrapping up from the previous storm and a bigger and more potent storm is only a day away at this point. Snow totals to this point have been impressive, with just about 3 feet of new snow recorded at road level since Sunday afternoon and more on the way. On Tuesday, Alpental Pro Patrol reported sensitive 12-14” soft slabs that were easily triggered with both explosives and ski cuts during their mitigation work. Combined with observations from recreationalists over the past few days, we are gaining some confidence that on Wednesday most avalanches should be confined to the recent storm snow (above the 1/2 interface). That said, there is limited information from upper elevations in the backcountry and we have lingering questions about deeper layers in the snowpack or the possibility of surprising avalanches. All of these layers should be put to the ultimate test on Wednesday night and Thursday as a major storm with elevated freezing levels and plenty of moisture heads our way. The timing of this storm is a little bit in question, so be prepared for rapidly changing conditions if you are out toward the end of the forecast period and the storm arrives early. Wednesday night will not be the time to spend a night in the mountains. 

The recent storm snow has again brought to light the dangers of snow immersion. You can read about this hazard here. As temperatures start to warm up with the incoming storm, take care around buildings and trees that will begin to shed large snow loads. Roofalanches and tree bombs are a real hazard that people have died from in the past.

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