Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
View on map

Avalanche danger

Mon
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
Open full map
Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Sunday is expected to be cold and clear, providing beautiful weather for playing in the mountains. You may not find a lot of avalanche hazard out there, but it’s not quite generally safe conditions. Be sure to look for unstable snow at upper elevations or if you’re stepping out into high consequence or extreme terrain.

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    The winds on Saturday night should be plenty strong enough to transport snow into small Wind Slabs for you to manage on Sunday. The question is if there is any snow available for the wind to transport? If so, you may find some slabs on aspects where you’re not used to seeing them due to the primarily easterly winds. You could also see some mid-slope or cross-loaded features, which are more prevalent during east wind events. The wind likes to deposit snow on the leeward side of ridgelines, on convex slopes, or near rocky features such as confined gullies or the base of cliffs. You’ll know you found an area to watch out for if the surface is dry snow as opposed to firm and crusty. 

    (1/28/2023)

    A small pocket of reactive snow near ridgeline on 1/28. Use small test slopes as you travel to check for cracking and unstable drifts.

    Photo: Brooke Maushund

Avalanche Discussion

Saturday’s weather event was not a big snow producer for Snoqualmie Pass. In fact, most of the day there were periods of sunshine and just a light breeze. A few flurries fell from the sky and winds increased in the afternoon. As stated above, stronger winds are expected this evening, but minimal new snowfall. Sunday should be cold and clear with decreasing wind speeds. Bundle up out there.

The benign weather comes on the heels of a more decent shot of snow dropped on the Pass on Friday when we picked up around 6 inches. Unfortunately for powder lovers, Friday turned sunny and warm, and a wet loose cycle followed. This destabilized the newly fallen snow and left behind a firm and crusty surface as temperatures dropped. 

This crust was reported by several parties in the Snoqualmie Pass region on Saturday and was found to ridgeline on most aspects. It could provide some difficult and potentially dangerous travel on Sunday as temperatures plummet and it solidifies even more. Some parties indicated that it does not exist on shaded slopes at upper elevations, but instead you could find settled storm snow. This could be the snow you're looking for to create small Wind Slabs on Sunday.

Additionally, a midstorm interface from Friday’s snow was found to be reactive by NWAC forecasters and avalanche professionals on Saturday. This layer was above the sun crust at the 1/27 interface but below the surface crust. If you are in an area that lacks a surface crust or it is easily breakable and thin, you may be able to trigger small avalanches on this layer on Sunday.

Deeper in the snowpack, we continue to monitor several other layers of interest, including the 1/21, 1/18, and MLK crust. On Saturday, NWAC forecasters found that these layers were still reactive in small column tests but not in large column tests. We’ll continue to watch them but do not believe that any of them present a widespread issue at this time. That said, you should focus any observations you make to the snow above the easily identifiable MLK crust and use that information to make terrain decisions.

Regions covered