Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

A few inches of new snow should be just enough to create the potential for avalanches in wind-loaded and steep sunny terrain. Even though most of these slides should remain small and easy to avoid, don’t let them take you for an unwanted ride into a creek or over a cliff.

Avalanche problems

  • Wind Slabs

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

    You’ll need to manage two different versions of the same problem Wednesday. Moderate winds could build fresh shallow slabs on the lee sides of exposed ridges, near convex rollovers, and in the tops of chutes. Look for pillow-like drifts where you see blowing snow or sharp wind lips. These new wind slabs may trigger easily but should remain fairly small and easy to avoid. 

    The trickier version of this problem will be isolated hard wind slabs that may have formed Monday. You’re most likely to encounter this issue in higher alpine cliffy terrain. To make matters worse, a few inches of soft snow could hide them from your view. The best way to avoid this problem is stay off of rocky complex slopes, especially where you see larger cornices. Snow shedding from above or other avalanches could release these slides naturally. Similar avalanches occurred on Tuesday in the Alpental Valley.

    (3/14/2023)

    This natural wind slab avalanche was first observed around 9am 3/14. Note the slightly older natural slides also at the base of the cliffs. Hemlock Peak, NE, 4900ft HS-N-D2-R2-U

    Photo: Katie Warren

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    A few inches of new snow is all that’s needed to create another round of natural loose wet avalanches. If the sun comes out, you’ll start to see snow shed from trees, rocks, and steep faces. This will likely trigger loose wet slides on the slopes below. So, if you’re starting to “feel” the sunshine, so is the snowpack. Pay attention to the terrain above you. Don’t linger on or under steep sunny slopes. With a new crust just under the surface, some of these slides could travel quickly downhill.

    (3/14/2023)

    Lots of rollerballs and fresh wet loose avalanches occurred with sunshine in Snoqualmie Pass.

    Photo: Katie Warren

Avalanche Discussion

While this doesn’t look like a very big storm, it could bring a quick 3-5in of snow to the Pass in the pre-dawn hours. That means the weather may still be a bit stormy in the morning before easing later in the day.

This time of year the snowpack is very aspect dependent. On southerly slopes, a new crust formed Tuesday. Sunshine and mild temperatures resulted in numerous rollerballs and snow shedding from rocky faces. The interesting thing was that some of this falling snow triggered wind slabs on the slopes below. In each case, the avalanche failed at the base of a cliff soon after the sun began to warm the steep face above. 

On more shaded slopes, cold dry snow remains. The recent storm brought just over a foot of snow to mid and upper elevations around the pass. This snow seems to be bonding well with the old interface (3/12). A widespread layer of graupel was reported within the new snow Tuesday. This could result in isolated shallow slabs on convex rollovers.

With the recent warm temperatures and rain, other issues like glide avalanches and natural cornices failures are on our minds. If you see crevasse-like cracks or overhanging blocks of snow, keep moving. Don’t hang out under these looming unpredictable hazards.

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