Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Sun
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

After a day of warm weather on Friday, we’re transitioning back to cold and snowy as we head into Saturday. As you ascend in elevation, you may have to steer around some dry snow drifted into piles by the wind. Keep tabs on how the weather is affecting the snow surface as it can be an indicator that we are flipping back to warm and wet problems in the afternoon. 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    Keep an eye out for shallow Wind Slabs to steer around at mid to upper elevations on Saturday. These potentially unstable pockets of snow like to form on the leeward side of ridgeliness, in confined chutes and gullies, or near rocky features such as the base of cliffs. Actively blowing snow, textured surfaces, or fresh small drifts behind objects are all visual clues you can use to help find where these slabs may be lurking. You can use small test slopes or uptrack tests to see how the snow is reacting to your weight or if it is cracking. Quick hand pits as you travel can help you determine how the new snow has bonded to the old snow surface.

    (2/24/2022)

    Example: Wind textured surfaces like this can indicate wind slabs on nearby slopes. 

    Photo: Andy Harrington

Avalanche Discussion

We’ve been on a springtime rollercoaster ride of weather at Snoqualmie Pass the last few days. As a result, avalanche concerns flipped from dry to wet and are now headed back toward dry (then potentially wet again). A cooler storm on Wednesday night helped drop up to 10” of storm snow at upper elevations around the pass. This cold snow persisted throughout much of Thursday and into Friday morning before warming temperatures were able to destabilize it in many areas. This led to a small wet loose avalanche cycle, with at least one larger spring shedding type avalanche observed by NWAC forecasters near Bryant Peak. 

Friday night into Saturday should be similar to our most recent storm, with cold dry snow totals being dictated by the presence of a convergence zone. If this snow producer lingers over the pass, expect higher accumulations and thicker slab avalanche concerns. If it doesn’t, we may only squeak out a few inches of snow resulting in more muted slabs or loose dry avalanches. On shadier slopes on the northern end of the compass, Wednesday night’s snow may not have fully warmed up on Friday. In these areas, you could find more layered cold snow to consider for potential slab avalanches above the 3/30 crust. 

Any existing cold dry snow, whether new or older, will be of concern for wet avalanches once temperatures warm or sunshine breaks through the clouds. This could be as early as Saturday afternoon or could wait until Sunday. If you notice the weather changing and that the snow is heating up or producing new rollerballs and pinwheels, be sure to start thinking about wet avalanches such as wet loose, cornice collapses, or glide. Springtime weather is dynamic and it often doesn’t take much to flip the snowpack from cold and dry to warm and wet. 

Additionally, this is the time of year the snowpack starts to shed its winter coat. Cornices that have built through multiple winter storms like to collapse and blocks of snow like to fall from rocky areas. These unpredictable shedding events can act as triggers on the slopes below, causing slabs to fail or larger debris piles. On Saturday, we expect most avalanches, whether they are wet or dry, to be isolated to the snow above the 3/30 interface. Below this melt-freeze crust, you’ll find a warm and weak springtime snowpack. A very large trigger from one of these shedding events could impact the snow below the 3/30 in isolated areas, so that’s another reason not to linger under these ticking time bombs.

Regions covered