Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Recent avalanches and poor snowpack structure should give you pause before stepping into consequential terrain. You are more likely to trigger an avalanche on steep rocky, convex, or wind-loaded features. If the sun’s rays are able to overcome the cool temperatures, keep an eye out for natural loose avalanches.

Avalanche problems

  • Storm Slabs

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

    Storm Slabs appeared to have healed considerably in recent days, but may still be triggered on specific terrain features such as convex or unsupported slopes over 35 degrees. The recent snow is generally right-side up, but has a few interstorm layers that you should investigate before committing to a slope. The caveat may be on slopes that see direct sunshine, where the top few inches may have stiffened up in recent days creating heavy snow over weaker snow. Use hand pits and test slopes to help you identify how the snow is bonded and reacting to your weight. Most of these slabs are very soft and when they fail, could look more like loose avalanches. You can categorize them however you like, but don’t get surprised and swept off your feet near terrain traps or other consequential terrain.

    If sustained east winds are able to consistently transport snow on Tuesday, you should be on the lookout for shallow Wind Slabs capping the new snow. East winds often produce slabs in different locations than you may be used to. So look for actively blowing snow as the easiest indicator that you need to put these freshly built slabs on your radar and to help locate them.

    (2/20/2022)

    This slab was triggered by skiers in the trees below Pineapple Pass on 2/20. 

    Photo: Public Observation

Avalanche Discussion

NWAC forecasters in the Alpental Valley on Monday found that most unsupported or convex slopes had shallow crowns on them from previous days. Many of the observed slabs were very soft and acted more like loose avalanches, making them difficult to differentiate. The snowpack was similar to what was found on Kendall Peak the day prior, and to what other professionals and recreationalists have reported. At mid to upper elevations, there sits around 20” of snow over the 2/19 interface. This thin melt-freeze crust is subtle but can be found just a few inches above the more easily identifiable Valentine’s Day Crust. Small column tests often failed on a midstorm layer of rimed precipitation particles, and also at the base of the storm snow at the 2/19 interface. 

Multiple loose avalanches were also observed on Monday, some human triggered and some triggered by solar activity. On Tuesday, these “sluffs” could be more of what’s in your face giving you direct feedback as you travel. As the day rolls along, keep an eye on how the snow is changing along with the weather. Temperatures should be chilly, but by the afternoon the clouds may dissipate resulting in full sunshine. The expectation is that the cool temperatures and breeze will keep most of the cold dry snow in place, but you could find some natural loose avalanches fail during this period, possibly triggering a lingering slab as they descend. 

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