Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

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

Another dynamic storm will bring rain, freezing rain, and possibly high-elevation snow to the Snoqualmie Pass zone on Tuesday. This will maintain dangerous avalanche conditions in the mountains. Stay far away from hanging blocks of snow or large avalanche slopes where unpredictable wet slides could descend.

Avalanche problems

  • Glide Cracks

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    As wet and wild weather continues, so will our concern for wet snow problems. With multiple nights above freezing and plenty of liquid water in the snowpack, the time for Glide avalanches may have arrived. These unpredictable and difficult to forecast slides can release the entire season’s snowpack or be as simple as large blocks of snow and ice falling from rocky ledges. Your best mitigation tool will be to limit the amount of time you spend below large avalanche paths, hanging blocks of snow, or slopes where you see large crevasse-like cracks in the snow. 

    While we often only pick one primary wet problem to call out, that doesn’t mean that you won’t encounter others if you venture into the mountains. Wet Loose, Wet Slab, and Glide avalanches are often intermingled. You may see Wet Loose avalanches as a precursor to the larger and more dangerous Wet Slab and Glide avalanches. Throw in sagging and failing cornices, and you have a variety of ways the wet and soggy snow can fail and produce avalanches large enough to bury or kill you.

    (12/26/2022)

    A glide avalanche in Shot 6 at Alpental, plus a separate Glide crack where the snow has not yet released. 

    Photo: Alpental Pro Patrol

Avalanche Discussion

The storm train keeps on rolling through Snoqualmie Pass. After multiple days of rain, freezing rain, sleet, and maybe a few flurries, get ready for some more Monday night into Tuesday. Water numbers to this point have been difficult to calculate, but our best guess is that we’re sitting somewhere in the 3.5 - 5.5 inch range since this “warm” spell began on 12/23. Expect continued rain at mid to upper elevations and freezing rain at lower elevations until temperatures start to cool some on Tuesday. 

On Monday, Alpental Pro Patrol relayed that Glide avalanches had started to occur around the resort, an indication that liquid water is percolating further into the snowpack. With continued rain and warm temperatures, there could be more of these unpredictable slides. At lower elevations, a sturdy freezing rain crust continues to cap the snowpack and hold things in place. However, instrumentation run by WSDOT’s avalanche team seems to indicate that liquid water is starting to find its way toward the ground at these lower elevations. You should expect to find difficult and slippery travel conditions due to this icy layer. You could also encounter swollen or blown-out creeks in many areas.

Even as temperatures start to cool Tuesday afternoon, you won’t be able to put these wet snow problems to bed. Water can linger in the snowpack and produce avalanches long after the rain has stopped (which it hasn’t yet). That said, by the end of the day, if you can make it through the lower-elevation ice fields and the mid-elevation driving rain, you could get into some snow with strong to extreme winds at upper elevations. If you find yourself in this more winter-like climate, be on the lookout for freshly building Wind Slabs on leeward slopes or near rocky features. We anticipate any new snow will bond fairly well to the wet and warm surface, but you could run into some trouble in those wind-loaded pockets.

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