Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 4 years ago.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

Highlights

The snowpack around Snoqualmie Pass will need some time to adjust to the recent rain. Give it the time it needs by avoiding slopes over 35 degrees until the surface starts to freeze. After big rain events, there’s always a bit of uncertainty around both avalanche and travel conditions, so make sure you have travel plans that give you plenty of terrain options.

Avalanche problems

  • Wet Slabs

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

    Even as the atmospheric river wraps up on Saturday, recent rain that has soaked our snowpack up to ridgecrest will still need some time to drain. Wet avalanches are not well understood and difficult to forecast, but they can occur long after the rain has stopped. These unpredictable slides are difficult to manage, so your best tool will be to avoid slopes over 35 degrees on Saturday where an avalanche can start, run, or stop. This includes being aware of the terrain above you such as sagging cornices, blocks of snow on rock ledges, or larger avalanche paths. 

     

    Wet avalanches could come in a variety of forms on Saturday, including Wet Loose avalanches starting from a point and fanning out as they descend, pockets of Wet Slabs, or larger Glides and Cornices. They could even be intermingled with loose slides triggering slabs for example. Regardless of what avalanche problem you encounter, your management of them will generally be the same. Put these slides on your radar anywhere you encounter wet and soggy snow.

    (1/13/2023)

    Large debris piles were found coming out of the Bryant Peak Couloir and surrounding bigger slide paths near Source Lake on 1/13.

    Photo: Trevor Kostanich

Avalanche Discussion

As of Friday afternoon, the Pass has received close to 1.5” of water during this atmospheric river event, and we’re not quite wrapped up yet. By the time Saturday morning rolls around, we should be getting close to 2” of precipitation since Wednesday night, most of which came as rain. While these water numbers are somewhat modest by Pass standards, make no mistake, there was some damage done to our snowpack around the zone. 

Rain runnels, swollen creeks, and wet avalanche debris have all been reported at lower elevations. On Friday, an avalanche professional in the Alpental Valley relayed that a natural cycle had occurred with multiple wet avalanches (both slabs and loose) up to size D2 observed. Observations from other locations and elevations up have been extremely limited due to the nasty weather, leading to a bit more uncertainty than we typically like to have heading into a holiday weekend. Prior to the atmospheric river, up to 2 feet of dry snow sat over the easily identifiable Christmas Crust, with a few layers of interest. Soaking rain likely has made its way to this prominent snowpack marker and may have shed a few of those layers in the process. 

As this event winds down, temperatures should slowly start to cool and winds should increase. This will help the snowpack to stabilize from the top down, eventually creating a new crust. When formed, this crust will be just one of the multiple surfaces you may encounter as you venture back into the mountains. Wet punchy snow, breakable crust, firm crust, swollen creeks, exposed natural hazards, and refrozen avalanche debris could all present different hazards as you travel. If you’re out there, please send us some pictures of what you’re seeing by submitting an observation.

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