Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

Sunshine and warm temperatures will help the snow heat up and could cause it to falldown. You’re most likely to encounter avalanches near and just above the rain-snow line. The largest slides could release from near rocky faces as they shed their recent snow.

Avalanche problems

  • Loose Wet

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

    You could be dealing with different versions of wet loose slides on Wednesday. The most common will be where several inches of recent snow sits on top of a firm crust. You’re most likely to see this around 4500ft and above. As conditions warm, this snow could slide. Sure, you may trigger these avalanches on steep slopes, but they could also occur naturally as snow sheds from rocks and trees. In most cases, these slides will be small and easy to manage, but on longer slopes, they could grow large and dangerous. 

    If these slides descend down into the wet, manky snow lower in the terrain, they could grow large and rumbly. These bigger slides would be most common below rocky features where larger avalanche paths descend into the forest from much higher up.

    Similarly, blocks of snow still cling to many rocky faces and glide cracks formed steep slopes. These shed avalanches could occur with little or no warning. For all of these larger natural slides, pay attention to the terrain above you. Manage your overhead hazard by limiting the time you spend underneath large, rocky avalanche terrain.

    (4/7/2024)

    A fresh large natural wet avalanche off the SE Buttress of Chair Peak. 

    Photo: Dallas Glass

  • Wind Slabs

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

    Near the tops of some of the higher peaks, the snow should eventually transition to drier more winter-like conditions. In these places, you could find more than a foot of new snow. Strong winds during this storm likely affected nearly every slope, stripping some and loading others. Scoured surfaces, fresh drifts, and sharp wind lips can help you determine local wind patterns. Avoid firm pillow-like slabs along ridgelines, below cliffs, and in the tops of chutes. Some of these wind-loaded pockets could be well below ridgeline on small convexities and along the sides of gullies. You might even see blocks of snow falling off cliffs or a collapsing cornice trigger wind slabs on the slopes below.

    Example: A wind slab in the top of a confined chute from earlier this season. 

Avalanche Discussion

Another dynamic spring weather day could keep you on your toes Wednesday. Choose routes with lots of options that help you adjust to the changing conditions. This could include leaving the mountains early as conditions really heat up. 

Wednesday has all the makings of a “greenhouse” kind of day at the Pass. Sunshine, warm temperatures, light winds, and just enough clouds to hold in the heat. These days are hard to predict, but often, when they occur they result in significant natural avalanche activity. 

We’re worried about all the snow above the Early April Crust (EAC). This will vary significantly with elevation. At 4000 ft, that might only be 4-8in, but above 5000 ft, it could be 1.5-2ft. That’s a lot of snow that could entrain in these avalanches. 

On Tuesday, the pass received more than an inch of water. At Pass level, that was rain, but above 4500ft, it was likely all snow. Given all the warm and rainy weather, expect thin coverage, open creeks, and wet, manky snow at lower elevations.

Regions covered