Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
3 · Considerable
Below
2 · Moderate
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Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Continued snowfall will maintain dangerous avalanche conditions Friday. Give the snowpack time to adjust to the added load of new snow. Steer around open slopes greater than 35 degrees where you can easily trigger an avalanche.

Avalanche problems

  • Storm Slabs

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

    Additional new snow Friday (3-6in) will bring storm totals over the past week up to 2ft+. Expect a warming trend with snow levels rising from 3000ft to 4000ft by the afternoon. Natural and human-triggered avalanches within recent storm snow could grow large. Avalanches may be easiest to trigger during periods of heavy snow or warming temperatures. Rain in the afternoon will create the potential for loose wet avalanche activity. You will likely encounter thicker and more reactive slabs in wind affected terrain at higher elevations. Simple uptrack tests and hand pits may easily highlight storm snow layers of concern. Continue to make assessments throughout the day. Conditions can change rapidly during storms like this.

    We’ve been talking all week about buried surface hoar and facets in the West-South zone. So far, we have not received reports of any avalanches on this layer. However, NWAC forecasters continue to find these weak grains in the snowpack. You’re most likely to find buried surface hoar or facets near treeline about 4” (10cm) above the very prominent 12/09 crust. If you see shooting cracks or feel collapses, seek out low angled terrain well away from steep slopes.

    (12/16/2020) This small storm slab avalanche occurred on a northeast aspect at 4400ft in Alpental Valley on Tuesday.

Avalanche Discussion

Any avalanche actively should remain above the very prominent 12/09 crust. This will make weak layers easy to observe since you can simply dig with your hand to investigate the recent layers and new storm snow. Rain and wet heavy snow could create a few small loose wet avalanches isolated to steep rocky slopes. The snowpack at lower elevations has been through a lot over the past few weeks with warm temperatures and other rainstorms. As a result, we don’t anticipate a significant hazard below the rain-snow line. Instead, expect challenging travel with areas of thin coverage, open creeks, and shallowly buried obstacles. 

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.

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