Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Expect avalanches concerns to shift from wet to dry as you ascend in elevation. You’ll most likely trigger a slide on features like convex rollovers, very steep slopes, and unsupported areas.

Avalanche problems

  • Storm Slabs

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

    Any single day’s storm totals aren’t impressive, but it’s stacking up, with over a foot of new snow since Jan 20th. You’re most likely to trigger shallow slabs in the most recent 24hrs of new snow (~6 inches). However, deeper avalanches could occur on one of the many storm layers from the past few days. Potential crusts within and at the base of the recent snow could make avalanches more likely at specific elevations. Small slopes and hand pits often identify possible weaklayers in the new snow. 

    The generally mild weather should help the new snow heal quickly. During times like this, it’s more about the features, than the bigger area. Convex rollovers, very steep terrain, unsupported areas, wind-loaded slopes, and the base of cliffs are all likely trigger points. Be leery of these spots especially when terrain traps exist below.

    (1/22/2024)

    Human-triggered slab on a steep unsupported slope. 

    Photo: Andy Harrington

  • Loose Wet

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

    Near and below the rain line, you’ll find wet, sticky, heavy snow. Avalanches will be most prevalent where the upper snowpack remained slightly drier and colder in the middle elevations. These slides can seem easy to predict and manage, but since they are wet and heavy, they can catch and carry you to places you don’t want to go. If you sink into wet snow past your ankle, then you can trigger one of these avalanches. Be careful on steep slopes, especially when they end in cliffs or creeks. 

    Other wet avalanches could occur during this prolonged mild period. Snow may shed from cliffs and glide off of smooth rock faces. Limit any time you spend underneath overhead hazards like steep rocky terrain.

     A natural wet avalanche during this mild period. (1/23/2024) Photo: Kevin Trippe

Avalanche Discussion

In some ways, Thursday feels like a “rinse and repeat” of every day this week. Mild, wet weather, with modest storm totals, won’t do much to significantly increase the danger, but it won’t allow it to drop either. By Thursday afternoon, the Pass could see another 4-6 inches of snow at mid-elevations. This will bring storm totals to around 18 inches since 1/20. Snow levels should continue to oscillate just above Pass level. 

Things were quiet on Wednesday. A few limited observations indicated that the recent rain only affected the upper few inches of the snowpack. Below the surface, things remain cold, dry, and layered. Various crusts exist in the upper snowpack. The most consistent is the 1/20 which generally occurs above 4500ft and may be quite stout and slick at upper elevations. 

For several weeks, we discussed the presence of a persistent weak layer of facets within the Solistice Crusts. This structure can still be found 3-5ft below the surface but hasn’t produced any known avalanches in quite a while. That’s not the same in other zones where activity continues. Even though things have been quiet on the Solstice Crust at Snoqualmie, it’s still worth having a conversation with your team about the consequences before stepping into large complex avalanche terrain.

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