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

As we roll back into cold and snowy weather, be sure to bring a winter mindset to the mountains on Saturday. Think about dry snow avalanche problems, particularly as you ascend in elevation where wind drifted piles are more likely. If you notice red-flag signs of instability like shooting cracks, avoid steeper features over 35 degrees. 

Avalanche problems

  • Wind Slabs

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

    Wind speeds Friday night and Saturday should be strong enough to easily blow around newly fallen snow to create Wind Slabs for you to steer around. Look for these unstable pockets of snow to develop on the leeward side of ridgelines, convex features, or near rocky terrain such as confined chutes or the base of cliffs. As you travel, visual clues such as actively blowing snow, textured snow surfaces, newly forming cornices, or fresh drifts behind objects can help you identify terrain where Wind Slabs may have developed. If you notice that the snow feels firm and hollow or it looks smooth and pillow-like, then you may have found wind-affected terrain to avoid. These slabs may be larger and more likely as you ascend in elevation but can form even down in the trees. Be sure to look for the signs and alter your terrain choices as necessary. 

    (2/1/2022)

    Example: Blowing snow and sharp drifts like this can help you find and avoid newly forming wind slabs. 

    Photo: Dallas Glass

Avalanche Discussion

A potent storm earlier this week had significant wind and dropped multiple feet of snow around Snoqualmie Pass. This storm had us forecasting High hazard focused around dry avalanches for the first time in weeks. Shortly after the storm’s duration, temperatures soared on Wednesday and Thursday, producing wet avalanche activity more in line with April conditions. Looking toward the weekend, our rollercoaster spring will continue as we again step into a cold and snowy pattern around the zone.

Wind speeds recorded at the top of Alpental gusted into the 60s on Friday afternoon and should continue at speeds capable of moving snow throughout the forecast period. A general cooling trend during this timeframe means that snow should be falling on a newly formed melt-freeze crust (4/8), where it is expected to bond fairly well initially. However, this is the springtime, and with that comes a lot of uncertainty around how the weather will play out. Variable winds, convergence zones, convective activity, and sun breaks could all be players on Saturday, so you’ll have to watch the weather to see how the day is unfolding. Here are a few things to keep in mind:

  • The location and duration of a convergence zone will dictate how much snow falls in our zone. This can be a hit-or-miss situation, so if you find that the snow has piled up more than you were expecting, dial back your terrain choices to more simple terrain. The more snow we get, the more widespread avalanche concerns will be. You might find that snow is failing in non-wind loaded terrain.
  • Convective showers could produce periods of graupel or hail, which then could be buried by additional precipitation or blowing snow. This is one of many ways a mid-storm weak layer could develop. Dig around with your hand or shovel down to the 4/8 crust to look for points of failure in the storm snow before committing to a slope.
  • It doesn’t take much sun this time of year to tip the scales and start producing natural avalanches. If there are periods of sunshine throughout the day, look for fresh rollerballs or snow shedding from trees and rocks as signs that small loose avalanches may follow. Depending on the duration of the sun, these could be dry or wet.
  • Most avalanches on Saturday should be confined to the snow above the 4/8 crust unless a very large trigger is involved.

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