Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

Dangerous conditions should develop quickly on a warm Thursday and will likely limit where you can travel safely.  There's a lot of recent snow for wet loose avalanches to entrain.  Avoid exposure to large slopes with overhanging cornices; they will be primed to fail and can potentially trigger larger avalanches on the slopes below.  

Avalanche problems

  • Loose Wet

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

    Wet loose avalanches happen all the time in the spring, so what makes Thursday different?  We just experienced a hearty, cold, winter-esque storm that dropped several feet of snow across the Cascades earlier in the week.  Now the weather dial is turning quickly toward spring with mid-mountain temperatures pushing toward 50F along with soaring freezing levels, and enough cloud cover Wednesday night making a solid refreeze unlikely.  This has all the trappings for human-triggered or natural wet loose avalanches, some that could run far distances and become deadly.  We also know there are fresh cornices along ridgelines primed to come down under the spring sun.  While high clouds and brisk SE winds will likely keep some slopes in check similar to Wednesday, we think the odds are heavily tilted towards more widespread and consequential avalanches on Thursday. 

    Wet loose avalanches will become likely early in the day following a mild Wednesday night.  Rollerballs and pinwheels will give you an initial heads up that the surface snow is becoming less cohesive. If you see natural wet loose avalanches, especially ones gouging down to deeper snow layers,  seek out simpler terrain that eliminates your exposure to overhead hazards.  

    (2/4/2022)

    Example: Natural loose wet avalanche occurring on steep sunny slopes earlier this winter. 

    Photo: Public Observation

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2.5

    Moderate SE winds moved snow along ridgelines on Wednesday.  While shallow new wind slabs may have formed on different aspects or cross-loaded some slopes, the main story is that there's still plenty of cold dry snow at upper elevations to become involved in avalanches on Thursday.  A cornice fall or a wet loose avalanche could trigger a slab avalanche deeper in the recent snow.   This is not a day to mess around with big terrain due to the overlapping avalanche problems. 

    You can identify wind-loaded terrain by seeking out textured surfaces, sharp drifts, and fresh cornices to anticipate where wind slabs may linger.  

    (4/2/2022) Example: Look for clues to help anticipate and avoid wind-loaded terrain.  Photo: Dallas Glass

Avalanche Discussion

Limited observations on Wednesday reported cold snow surfaces changing to moist by mid-morning at low and mid-elevations as temperatures increased and the sun climbed.  A sizeable natural wet loose avalanche was observed on the south side of Low mountain (west and above Denny Cr).  Increased cloud cover and winds may have kept more widespread wet loose activity at bay.  

As of Tuesday afternoon (5 pm) Snoqualmie had received around a foot of snow at pass level with more than 3 feet at the top of Alpental. Very strong and gusty westerly winds persisted throughout the two-day storm. This snow sits on the Early April Crust. You can use this prominent snowpack marker to help measure new snow depths and to focus your observations above this layer. We don’t anticipate slides involving deeper snow layers at this time.

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