Avalanche forecast

Snoqualmie Pass

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
3 · Considerable
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

A brief lull in the weather on Friday could result in a decrease in avalanche potential. There's still plenty of storm snow, especially as you ascend in elevation, so be leery of convexities, confined gullies, or wind-loaded terrain where triggering a slab is more likely. If the March sun is out for long, it could destabilize the surface, causing natural avalanche activity.

Avalanche problems

  • Wind Slabs

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

    In wind-loaded terrain, the new snow is piled deeper, and could fail more easily on Friday, so it gets the nod as the official problem. But you could consider this a "new snow problem," like our friends in Utah would say. Wind slab, storm slab, snow heating up in the sun resulting in loose or slab avalanches - they all involve the new snow. Look for textured surfaces, large drifts, fresh cornices, or actively blowing snow to help determine wind-loaded slopes. Areas such as leeward ridgelines, the base of rocks, confined chutes/gullies, and convex slopes are all classic locations where wind slabs like to form. Most reported avalanche activity over the last few days involved wind-loaded terrain. Don't make the same mistake on Friday, if you suspect a slope is wind-loaded, steer around it.

    That new snow could fail in other ways in sheltered areas such as loose or storm slabs. Use your uptrack tests, hand pits, and small test slopes to look for cracking of the surface or blocks of snow failing easily. If you get concerning results, dial it back and avoid all slopes over 35 degrees. These tests work well to assess wind-affected terrain as well. 

    (3/13/2025)

    A natural wind slab up in the rocks released on Mount Snoqualmie during the early morning hours of 3/13.

    Photo: Roger Strong

  • Loose Wet

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

    This problem also involves the new snow, but with a caveat. It will need the March sunshine to help kick it off. That's not a sure bet on Friday, but there could be enough clear hours that talking about solar-induced avalanches is worth an official problem.  If the sun is out, it could destabilize the surface, resulting in wet avalanche activity such as rollerballs, pinwheels, and natural avalanches. It could also help the new snow "slab up" and become more sensitive on steep slopes. If you feel the snow surface getting wet, consider heading for lower-angled slopes in the shade. Be sure you are aware of slopes above you that could be basking in the sun and shedding snow.

    (3/12/2025)

    A human-triggered avalanche in moist snow on Mount Snoqualmie. Similar slides could occur if the sun is able to destabilize the surface on Friday.

Avalanche Discussion

We're in the midst of a stormy week at Snoqualmie Pass.  After a few days of snow, wind, and avalanches, Friday should be a lull before the weather ramps back up again on Saturday. Most reported avalanche activity this week has been confined to the storm snow sitting above our most recent atmospheric river (AR) crust. This easily identifiable snowpack marker gives you something to target when making your infield assessments. The depth of new snow varies considerably based on elevation and location within the zone. On Thursday, an NWAC forecaster found as little as a few inches to as much as 2 feet while traveling on Kendall Peak. That's quite the spread - so pinpointing which layers exist where isn't easy. You'll have to frequently check for yourself wherever you are traveling. In locations with more than a few inches of snow over a crust, you may find that the 3/9 interface fails easily in handpits or more formalized tests. It has been suspected in a handful of avalanches from earlier this week, and in some locations, it may contain buried surface hoar.

The real head-scratcher is that a glide slope at Alpental released midday down to the rock on Thursday. Lower elevations were damp on Wednesday, and many parties reported wet-related slides. This avalanche is a good reminder that it can take a while for water to work its way through the snowpack, and unusual weather can lead to unusual avalanches. We're talking about an uptick in wet avalanche potential on Friday due to solar input, but we're not expecting more honkers like what happened at Alp on Thursday. 

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