Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

You may still need to manage Wind Slabs of varying ages as you ascend in elevation on Wednesday. Keep a keen eye for larger drifts on convex features or near rocky chutes and gullies where triggering an avalanche in wind-drifted snow is more likely. The sun should come out and might facilitate some small slides as snow sheds from trees and rocks. 

Avalanche problems

  • Wind Slabs

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

    An uptick in winds on Wednesday afternoon could be enough to create a fresh round of Wind Slabs for you to manage at mid to upper elevations. They could intermingle with existing slabs formed due to windy weather in recent days. Since the wind direction has been flip-flopping this week, you could find them on a variety of aspects. You should be able to use visual clues such as blowing snow and fresh drifts to help identify newly forming slabs. You may need to feel for differences in the density of the snow as you travel to help pinpoint older ones. Regardless of their age, you’re more likely to encounter wind-drifted pockets near rocky features such as confined gullies or the base of cliffs, on convex rollovers, or the leeward side of ridgelines. If you suspect a slope to be wind-loaded, steer around it.

    (2/23/2023)

    A skier triggered a Wind Slab in a confined terrain feature on a sunny day after our last storm.

    Photo: NWAC Public Obs

  • Loose Dry

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1

    With cold dry snow in place and the sun expected to come out for a few hours tomorrow, we can’t rule out some solar-induced loose avalanches. For this one to pan out, March sunshine will need to overcome cold temperatures combined with increasing winds and clouds throughout the day. If it can, you could see snow start to shed from rocks and trees, triggering avalanches on the slopes below. The moisture content of the snow may be somewhere between Wet and Dry, but the behavior should remain the same. These avalanches should start at a point and fan out as they move downhill. While many travelers regard loose avalanches as easy to manage, be sure not to get surprised by one near a terrain trap. Choose travel routes where you can stay aware of steep slopes receiving direct sunshine above you.

    (2/13/2023)

    Example: A small loose avalanche triggered by snow shedding from trees a few weeks ago.

    Photo: Dallas Glass

Avalanche Discussion

Wednesday should be a relative break in our snowy weather with the sun making an appearance before another stormy period begins in the evening hours. The Pass has picked up around 1.5 feet of snow since 2/25, most of which has been low-density and reportedly poorly bonded to the prior surface. 

Avalanche professionals and Alpental Pro Patrol have reported actively blowing snow, small Wind Slab avalanches, and plenty of loose snow available to run on an underlying crust in recent days. We don’t envision much change on Wednesday, except you could see the snow start to “slab up” a bit more if the sun stays out for a prolonged period of time. Any triggered avalanche has the potential to run far and fast at the 2/25 interface, but we do not anticipate any deeper slides at this time. The only caveat would be some sort of isolated Glide avalanche due to warming. We have received reports of the famous Glide slope at Alpental sagging in recent days but haven't heard of any other new glide cracks. It would be a surprise if Wednesday was the day to tip the scales on this frequent flier.

A bit of a trivia: For the past two seasons, Chair Peak in the Alpental Valley has produced very large and destructive avalanches on March 1st - both times reaching Source Lake. As we turn the calendar to the first day of meteorological spring, the avalanche conditions don’t appear set for a three-peat. But if you’re superstitious, you may want to find somewhere else to play just in case.

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