Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
View on map

Avalanche danger

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Out of date — this forecast expired 3 years ago.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

Highlights

Winds will taper off overnight, but you could still trigger avalanches in lingering unstable pockets of stiff wind-drifted snow. Look for deep, textured drifts to identify potential wind-affected terrain. Steer around steep slopes where you find these hollow-sounding drifts or observe cracks shooting away from you. 

Avalanche problems

  • Wind Slabs

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

    The winds likely did some damage on Tuesday, with 18hrs of steady wind speeds over 20mph. Finding locations where this wind event did not impact the recent snow may be challenging. Expect widespread textured surfaces and stiff wind-board. The poor weather and travel conditions left us with minimal observations on the distribution and sensitivity of the wind slab problem. However, you will likely find them throughout the terrain on convex rolls, below ridges, at the base of cliffs, and cross-loaded gullies. While Wednesday will be a much milder day with calm winds, you should approach any steep wind-affected slopes with suspicion. Steep, confined, rocky terrain will be the most likely location to trigger one of these avalanches. Wind slabs likely formed over various surfaces, including slick crusts and weaker snow, so they could take some time to become unreactive. If you identify deep, hollow-sounding drifts or observe any obvious signs of instability, such as cracks shooting away from you, move to lower-angle terrain or sheltered forested areas

    (3/25/2023)

    Confined, rocky terrain features are likely locations to find lingering unstable wind slabs. 

    Photo: Public Observation

Avalanche Discussion

With cloud cover in the forecast, it won't be the next sunny day you have been waiting for, but calm wind and increasing temperatures should once again put wet avalanches on your mind. Widespread crusts and wind-affected snow will likely limit the extent of this problem, but you may still see some small wet avalanches tomorrow. Pay attention to the consistency of the snow below you and move onto lower-angle terrain if wet, heavy snow is easily sliding downhill.

Last week's snowfall overlays a melt-freeze crust on most aspects except high-elevation northerly slopes (3/22 interface). Multiple shallow (3-10") soft slab avalanches were human-triggered over the weekend, failing within or at the base of the recent storm snow. Most of these slides appeared to be on steep convex slopes or near rocky terrain, such as rocky chutes or the base of cliffs. Avalanche professionals and NWAC forecasters identified pockets of weak snow, with a few whumpfing collapses experienced on west aspects at mid to upper elevations. 

We had some concerns about weak snow buried during this storm. If it survived, the distribution is spotty at best, but it could explain some of the collapses or a few of the triggered slabs. We are continuing to gather more information about this potential weak layer in the snowpack. So be sure to check the bond on the 3/22 interface and the snow above it as you travel on Monday. We expect any avalanche activity to occur at or above this interface.

Regions covered