Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
4 · High
Treeline
4 · High
Below
3 · Considerable
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Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

An atmospheric river will result in very dangerous avalanche conditions at Snoqualmie Pass. Traveling in terrain where avalanches can start, run, or stop is not recommended. Better to stay home and play with your new toys or start your New Year's diet early than tempt fate in the mountains.

Avalanche problems

  • Storm Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Very Likely
    Size
    2

    This is a big storm! Heavy precipitation, strong winds, and fluctuating freezing levels all point toward unstable conditions and natural avalanche activity on slopes greater than 35 degrees. We anticipate several rounds of natural avalanches on Wednesday night and during the daylight hours on Thursday as the snow piles up.  Even though a slope has already shed doesn't mean it can't reload and release again.  Accompanying extreme wind speeds will result in wind slabs on leeward slopes. The travel advice remains the same. Don't try to overthink this one - stay far away from all areas where avalanches can start, run, or stop. 

    (12/17/2024)

    Natural avalanche activity during our last atmospheric river. High precipitation rates overloaded this seemingly inconsequential slope to produce a shallow slide.

    They'll be bigger on Thursday.

    Photo: Eddie Schoen

  • Loose Wet

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

    A bump in freezing levels is expected mid-morning on Wednesday. This could result in a switch to rain at lower elevations, particularly on the west side of The Pass Proper. If rain starts falling on dry snow, wet avalanches will follow. Although they may not be large or widespread enough to warrant High avalanche danger at this elevation, they will still be dangerous. Your best bet is to stick to the travel advice from the previous storm slab problem and avoid terrain where avalanches can start, run, or stop. 

    (12/18/2024)

    A large pile of wet avalanche debris from natural avalanches due to rain on snow earlier this month.

    Photo: Summit at Snoqualmie Pro Patrol

Avalanche Discussion

If you were hoping to take your new toys out to play in the mountains or work off some Chinese food on Thursday, we've got bad news.  A potent storm will slam into Snoqualmie Pass Wednesday night and throughout the day on Thursday, resulting in avalanches large enough to bury and kill you. We'll be measuring snow in feet, not inches, during this one. As a result, several rounds of large natural avalanches are expected before this storm concludes.

We don't anticipate seeing any avalanches break below the Solstice Crust. As of Wednesday, you could find this stout interface up to a foot below the surface at mid and upper elevations. It will create an excellent sliding surface for avalanches to run on and potentially travel long distances toward lower elevations.

The only real question mark with this storm is the freezing level. It will fluctuate and is expected to bump up around mid-morning on Thursday.  When it does, watch out for a change from dry to wet avalanche problems.

Looking ahead, plenty of storms are lined up for the rest of the week. Hopefully, by week's end, The Pass will be "in" and we'll be able to tone down the difficult travel talk at lower elevations. You shouldn't have to worry about those travel conditions tomorrow, though, because you're going to sleep in and avoid avalanche terrain until this storm plays out.

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