Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Sunday should provide the last remnants of fair weather before a potent storm hits the area Sunday evening. Expect increasing hazard and wind speed as the day progresses and the storm nears. Even low elevation areas on both sides of the pass proper will be susceptible to unusual wind loading patterns during the day, so evaluate your travel routes carefully. 

Avalanche problems

  • Wind Slabs

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

    As the winds pick up on Sunday, keep an eye out for actively blowing snow as your easiest indicator of freshly formed Wind Slabs. The low-density snow surface should be easily transported by the strong winds toward the lee side of ridgelines or near rocky features such as the base of cliffs and confined chutes. Be aware of the potential for unusual loading patterns due to the forecasted east wind event. Mid-slope loading and cross-loading are often more prevalent at Snoqualmie Pass during these events and you may find Wind Slabs on slopes where you do not frequently see them. If the snow surface feels firmer, appears to be hollow, or looks textured, those are good indicators that you are in wind-loaded terrain. You can use small test slopes to look for cracking or see how wind-stiffened snow is reacting to your weight. If you suspect an area to be wind-loaded, avoid it by seeking out more wind-sheltered terrain.

    (12/23/2021)

    Tracks being filled in throughout the day indicate lots of blowing snow and the possibility for wind slabs in nearby terrain.

    Photo: Robert Hahn

Avalanche Discussion

On Sunday, minimal snow should fall during the daylight hours before the bulk of the storm hits Sunday night into Monday. The new snow should be falling on a generally right side up snowpack made up of mostly low-density snow over the Solstice Crust. Keep this low-density snow and the potential for loose snow avalanches on your mind as you travel. We anticipate most avalanche activity to occur above the 12/29 interface but can’t rule out a step down to the Solstice Crust in isolated areas. Reports of very large avalanches have slowly trickled in over the past week from around the region and many of these avalanches are suspected to have failed down to the Solstice Crust. The most recent example was at Mt. Baker on 12/31 where a D3 avalanche left behind a ~550 foot wide, 2-5 foot deep crown. Only last week, we saw a similar avalanche in our own zone in the upper Chair Peak basin. Although these avalanches appear to be erratic and unpredictable, most appear to have occurred in wind-prone alpine terrain around the depth of the Solstice Crust. Take this information with you if you plan to travel to similar terrain on Sunday.

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