Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Sunday’s weather looks beautiful! However, sunshine and warm temperatures could cause some slopes to avalanche naturally. Plan your day to travel and return early, so you don’t happen to be under one of these areas if it sheds.

Avalanche problems

  • Loose Wet

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

    A solid overnight freeze will limit the loose wet hazard in the morning. So, plan to travel while the surface is firm or just starting to soften. Once your boot sinks in past the ankle, the danger is rising. Rollerballs and fresh piles of fan-shaped debris should tell you that the scales have tipped and natural loose wet avalanches will occur on similar slopes. While you may trigger one of these wet slides, the real danger comes from snow falling down on you. As the surface crust breaks down, some of these avalanches could gouge into older snow layers and run long distances. A public observation near Source Lake on Saturday describes a slide just like this. Pay attention to the terrain above you and anticipate that rocky slopes basking in the sun may soften much faster than lower angle and shaded areas. While a cool breeze and a few high thin clouds will fight to delay wet snow issues, we think the strong April sun and warm temperatures will eventually win and dangerous avalanche conditions will develop.

    (4/23/2022)

    This large natural loose wet avalanche occurred on 4/23, crossed a common travel route, and nearly caught a party of 5 travelers. You could see similar slides on Sunday.  ESE, 5200' LW-N-D2-R1-S Chair Peak

    Photo: Public Observation

  • Cornices

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2

    Cornices are a normal mountain hazard. So, when we start listing them as a problem, we’re worried they may start falling down on their own. Predicting exactly when and where this could occur is nearly impossible. However, another warm and sunny day could have the mountains shedding some of their winter load. This means cornices might collapse and blocks of snow could fall from rocky faces. While we don’t think this will be a large or widespread cycle, you don’t want to be under one of these features if it releases. Choose routes that help limit the amount of time you need to spend under these potential hazards.

    (3/28/2022) Example: These blocks of cornice trigger fell and triggered loose wet slides earlier this winter. You could see similar conditions Sunday.  Photo: Dallas Glass

Avalanche Discussion

Saturday night should be cold and clear. This will allow most surfaces away from the forest cover to freeze solid despite some locations remaining above freezing. Temperature inversions could make the trailheads quite chilly in the morning, but don’t worry, it will warm up quickly. There’s always a lot of uncertainty when talking about these wet avalanche cycles following a colder snowy period. However, if Saturday’s avalanche observations are any indication, we anticipate Sunday will be more active or at least produce larger avalanches. 

We’re mainly worried about the upper snowpack above the prominent 4/8 curst. You’ll find this layer about 2-3 ft below the surface on most slopes. As conditions warm on Sunday, you could see avalanches involving some or all of this snow. Fortunately, we aren’t currently worried about deeper layers in the snowpack. 

This is NWAC’s last daily avalanche forecast for the 2021-2022 winter season. Mt Weather Forecasts will continue until May 1. Make sure to check our Spring Avalanche Statement for information and travel advice. NWAC will continue to track snow and weather conditions. Large storms and/or widespread avalanche cycles may cause us to issue special avalanche bulletins, avalanche warnings, or other spring statements to keep you informed.  You can help your backcountry community by continuing to submit observations of avalanches, snow, and pertinent weather to our site. 

Have a fun and safe spring recreating in the mountains!

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