Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
View on map

Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
Open full map
Out of date — this forecast expired 5 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Continue to let the consequences of being caught in a very large avalanche drive your terrain selection on Friday. Several days of warm weather, recent deep avalanches, and incoming precipitation and wind are enough to maintain dangerous avalanche conditions. 

Avalanche problems

  • Deep Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    3

    The Mid-January crust that we have been tracking has been the culprit in some very large recent avalanches and currently exists about 10 feet (300cm) below the surface at Snoqualmie Pass. The timing of these destructive avalanches is almost impossible to predict, but if they fail, they will be very large, and being caught would almost certainly be fatal. The best way to mitigate your risk is to choose terrain that avoids large start zones, avalanche paths, and runout zones. These slides have been running long distances toward valley bottoms and approaching maximum runouts. Many areas we often consider as “safe” do not currently fit that description. 

    (3/1/2021) A very wide, very deep avalanche released from the east bowl of Chair Peak at some point between Sunday night and Monday morning (NE-E-SE 5800; HS-N-D3.5-R4-O). Photo: Bryce Hill

Avalanche Discussion

Temperatures should remain elevated at Snoqualmie Pass for a good chunk of the day on Friday. These temperatures, recent avalanches, confirmed poor snowpack structure, and possible precipitation are enough red-flags for us to be concerned for more natural Deep Slab avalanches. We have some uncertainty around what it would take to trigger one of these slabs at this time, but we believe that a large cornice fall could do the trick. The continued warm temperatures and some light rain will only further destabilize cornices and blocks of snow sitting on rocks and cliffs, increasing the possibility of them falling. Glide cracks have recently opened up, and on Thursday Alpental Pro Patrol reported that a chunk of one of their Glide Slopes had fallen off overnight. This helps to illustrate the issues created by warmer temperatures and the erratic nature of these types of avalanches. Continue to be leery of slopes with an overhead hazard such as cornices or rocky slopes with large cracks in them. If you’re on a ridgeline, don’t get too close to cornices, they notoriously break further back than you expect them to. The light rain could also trigger a few lingering Wet Loose avalanches, particularly on slopes that haven’t seen direct sunshine recently. Remain vigilant with your terrain selection and let the consequences of the Deep Slabs guide you.

During the ongoing Covid-19 pandemic, continue to follow the latest guidance from local, state, and federal health officials. Avoid unnecessary risks that could impact first responders and stress medical resources.  Wear a mask when appropriate, practice social distancing, and consider recreating closer to home.

Regions covered