Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 7 months ago. You’re viewing past conditions, not the current bulletin.

Highlights

Rain, high freezing levels, and increasing sunshine will all contribute to creating a warm and weak upper snowpack. Wet avalanches could fail naturally or be easily triggered by humans, particularly at upper elevations. Don't get pushed into a terrain trap or thin area by one of these slow-moving, but dense slides.

Avalanche problems

  • Loose Wet

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

    Uncertainty in the weather forecast makes the nitty-gritty specifics of this problem tricky to pin down. Luckily, you can simplify your life by looking to the snow surface. If you find yourself sinking into moist snow deeper than your ankle, you should be concerned about wet avalanches.

    While lower elevations may only produce a few rollerballs, it will likely be a different story as you ascend. Up higher, the size and reactivity of these avalanches should increase. Largely in part due to deeper recent storm snow sitting over a great sliding surface in the January Drought Interface.

    Some avalanches may fail naturally in the heat of the day. You may see blocks of snow shedding from cliffs or rocky ledges, creating slides on the slopes below. Furthermore, anywhere the snow is moist, it could be primed for you to easily trigger a wet slide on steep slopes. Once initiated, any wet avalanche could grow large as it descends. Don't get caught in one of these slow-moving slides, especially near terrain traps. 

    Your approach to managing this problem is to head for lower-angle terrain, keeping an eye on slopes above you that could shed the recent storm snow.

Avalanche Discussion

Mother Nature is flip-flopping all over the place. We've bounced back and forth between snow and rain for almost a week now, culminating in rain and rising freezing levels on Monday. We expect rain to have reached ridgecrest throughout the zone Monday night, creating a wet and weak snowpack. On Tuesday, we start moving into high pressure for the rest of the week. During this period, freezing levels should remain elevated, and sunshine will begin to take hold of the zone, although the cloud forecast for Tuesday is uncertain.

Rain, high freezing levels, and sunshine. They're all inputs for producing wet slides, and that's what you should focus on. The initial shock to the snowpack may be over by Tuesday morning, but at upper elevations, over a foot of recent snow was already on the ground before the rain hit. That snow should be warm and weak and, in many areas, it overlays a stout crust- the January Drought Interface (JDI). This is the snow we are worried about creating avalanches this week, particularly on Tuesday.

Although weak snow above the JDI has been identified, reports indicate it has already been wetted in most locations. This will help limit the potential for widely breaking or surprising avalanches. But keep an eye out for slab avalanches of any kind. If you see them, dial your terrain selection way back. 

This upcoming week will not help alleviate the travel hazards and "early-season" conditions that have plagued us most of the winter. Holes, creeks, bushes, rocks, ice, and bare ground are commonplace throughout the hillsides.

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