Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

The snow totals might not catch your attention, but it’s spring, and the conditions are very dynamic. You could trigger avalanches within the new snow regardless of aspect. As the sun comes out, you may find that slides become easier to trigger, especially on southerly-facing slopes.

Avalanche problems

  • Loose Wet

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

    On Saturday, travelers reported wet, heavy new snow. Small natural and triggered loose wet slides occurred on all aspects. Some even gouged into the older snow allowing them to grow larger. Unless the snow dries out overnight, we expect very similar conditions on Sunday. 

    As you ascend, you’ll find more and more new snow. If you create mini avalanches and rollerballs when there are only 2-3 inches of snow, then you’ll almost certainly be able to produce real avalanches higher. If the underlying snow is wet and punchy, these slides could entrain deeper layers and flow more like cement. You don’t want to be caught in one of these bigger wet slides. 

    Increasing sunshine and mild temperatures will help the snow warm quickly. This could release a barrage of rollerballs near rocks and trees. It could also result in natural wet avalanches. These slides will be most prevalent on steep sunny slopes but could happen on all but the most shaded northerly slopes.

    (2/3/2024)

    Example: A pile of rollerballs from a brief period of sunshine on a few inches of recent snow. 

    Photo: Ian Nicholson

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    Somewhere in the upper elevation band, the snow probably transitions from wet to dry. If you venture toward the tops of the higher peaks pay attention to places where you’re most likely to trigger shallow slab avalanches. Be leery of convex rollovers, unsupported slopes, and wind-affected areas. Hand pits, up track tests, and small slopes can help you see how the snow reacts. As the sun comes out, these slabs could start to change. Sometimes that means they’re easy to trigger, sometimes harder. Plan for these changing conditions, and don’t hinge your day on a few observations.

    (2/28/2024)

    An uptrack test failing on the old/new interface and cracking. 

    Photo: Dallas Glass

Avalanche Discussion

A few showers in the morning should give way to clearing skies and warming temperatures. It’s springtime, and the weather and snowpack often change at alarming rates. What may not feel particularly dangerous can turn on a dime. 

An extended period of warm weather caused cornices to fail and released several glide avalanches. These won't stop instantly. Even if they're becoming much less likely, pay attention to what's above you and limit any time you spend below rock faces still holding blocks of snow. 

We know very little about the upper snowpack at the Pass. Observations seem to indicate a high level of variability. This isn’t surprising, given the recent spring-like weather. At lower elevations, the snowpack took a huge hit. Debris, open creeks, and exposed obstacles are common. There isn’t much, if any, new snow down in the dark forest. At middle elevations, the new snow increases quickly from 2-4in at 4000ft to 6-8in above 5000ft. A few more inches could accumulate Saturday night and add to these totals. What’s underneath is also variable. In many places, a weak breakable crust caps older wet snow. In other spots, no crust exists. We have even less information about the upper elevations. As a result, we have lower confidence in our forecast higher in the terrain. 

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