Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
3 · Considerable
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Highlights

You may encounter dangerous avalanche conditions Tuesday morning as additional snowfall and strong winds continue to build unstable slabs. Some of these slides could trigger easily and grow large enough to bury you. Avoid traveling on steep open slopes until the snowpack has time to heal.

Avalanche problems

  • Storm Slabs

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

    The best way to describe the conditions is “stormy.” That includes strong winds and periods of heavy snowfall. It will take a bit for the snowpack to adjust to the new load and gain strength. So, even as the storm starts to taper Tuesday afternoon, expect conditions to remain dangerous. That means you could encounter a large natural avalanche or trigger slides on steep open slopes greater than 35 degrees. 

    This will be particularly true in wind-loaded areas. Blowing snow and sharp drifts can help you identify where these firmer and deeper slabs may exist. 

    Stick to smaller slopes, lower-angled areas, and well-treed terrain to avoid these problems.

    (2/20/2023) This large storm slab avalanche occurred during a warmup around lunchtime on Monday 2/20. SW, 5500ft, SS-N-D2-R2-U Photo: Dallas Glass

Avalanche Discussion

Avalanche Accident Colchuck Pk, East Central Zone

We’ve received preliminary information of an avalanche incident on Colchuck Peak, SW of Leavenworth, WA. (East Central Zone) The accident occurred on Sunday, February 19 and involved a group of 6 backcountry travelers. Three members of the group are suspected to have been buried and perished in the event. Another sustained injuries and was evacuated by SAR.  Rescue efforts are ongoing. NWAC is working with Chelan County Sheriff’s office and will make updates as more information becomes available.

 Forecast Discussion:

A significant winter storm will continue to impact the Snoqualmie area through Tuesday. Avalanche danger may peak Monday night during the height of the storm. This could include a more widespread natural avalanche cycle. Since precipitation and winds should decrease throughout the day, you’ll likely find the greatest danger first thing in the morning. 

The new snow may contain several inter-storm layers from changes in temperature and/or precipitation rates. These could vary greatly by elevation. Expect the largest potential avalanches at mid and upper elevations and in wind-loaded terrain. Closer to Pass level, less new snow should result in smaller slides. With cooling temperatures, even if you don’t see the classic strong over weak slab structure, expect loose dry avalanches that could run quickly on the newly forming crust. 

On Monday, the storm didn’t quite materialize as we thought. Even still, in a very quick tour, an NWAC forecaster found 4 very recent large (D1.5-2) storm slab avalanches on Kendall Peak. Alpental Patrol also reported easy to trigger slabs and cornices at mid and upper elevations. Lower in the terrain, the soft surface snow soaked up the incoming water. Only a few very small wet loose slides were observed. This wet snow will result in yet another new crust in the snowpack up to at least 4500ft. 

We still think avalanche activity will remain within the new snow. While it’s not out of the question for an avalanche to fail at the 2/17 or 2/13 interfaces, these events would likely be rather isolated.

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