Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Don't get lulled into a false sense of security by the beautiful, spring-like weather. Weak layers, capable of producing dangerous avalanches, are lurking in the upper snowpack. Choose terrain carefully and remember that all steep slopes are currently suspect.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Likely
    Size
    1.5–2.5

    The threat of persistent weak layers in the upper snowpack failing should be shaping your travel plans on Sunday. While the likelihood of triggering these layers is a point of discussion, there is no disagreement among anyone who has taken the time to look - they are there, and they are spooky. This snowpack setup is atypical for us here in the Cascades, so you can't just roll out your normal playbook and assume that you'll get the same results as you always do. Take the time to discuss your acceptable level of risk with your partners. Then make careful trip plans that give you the option to avoid open avalanche terrain over 30 degrees. 

    This problem is difficult to diagnose in the field, so you likely won't receive much feedback before an avalanche occurs. Maybe you'll get a whumpfing collapse or a shooting crack, but that's not a guarantee. Even using test slopes or uptrack tests won't help you identify where this problem could rear its ugly head. If a persistent slab avalanche occurs, it could break widely or even be triggered remotely (from a distance). The only mitigation tool you have is terrain avoidance. 

    (2/27/2026)

    A widely-breaking avalanche in the Sourdough Range of Mount Rainier National Park. This one doesn't have a confirmed failure date, but you can bet it's persistent by how wide it is.

    Photo: Crystal Mountain Pro Patrol

  • Loose Wet

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

    Is March 1st too early to talk about spring? Maybe so, but you'll likely find some springlike weather in the mountains on Sunday, leading to the possibility of wet avalanches. 

    If the surface is getting warm and sticky or you see snow shedding from trees and rocks, you'll know that wet avalanche activity could soon follow. That will be your cue to head for shaded, low-angle terrain, staying aware of slopes above you.

    This avalanche problem is typically easy to manage, but with persistent weak layers lurking below the surface, it becomes more complex. In addition to fanning out and growing in size as they descend, the threat now exists that they will trigger larger and more dangerous persistent slab avalanches. 

    (2/28/2026)

    Some of these wet loose slides are old, some are new. While not necessarily widespread, there were several natural wet loose slide across the valley in the Paradise areas. 

    Photo: Dallas Glass

Avalanche Discussion

Saturday marked a change from cool and windy to warm and sunny in the West South zone. We didn't break any heat records as we said goodbye to February, but weather station temperatures made their way into the 40s and the sun poked through the high clouds. As a result, wet avalanche activity was reported from several areas of the zone. Most of these slides were on the small side, but some ran impressive distances. Wind-affected surfaces and pockets of wind slab were also reported - a result of the strong wind event that occurred on Thursday and Friday.

As Sunday dawns, a new surface crust will likely exist on slopes that got warm and sticky on Saturday. This superficial freeze will likely break down as temperatures climb higher and that March sunshine pours through high clouds. Expect similar avalanche activity to what was observed on Saturday. 

The main question on everyone's mind is how our persistent weak layers will respond as this warm-up continues. The 2/13 and 2/7 layers contain surface hoar and facets and can generally be found in the top couple of feet of the snowpack. These layers have produced widely breaking avalanches throughout this week. We've been in a bit of a lull for a day or two now, but that doesn't mean this problem is dead. It's a long way from the West South, but on Saturday afternoon, a very large natural avalanche failed near Mount Baker, likely due to solar influence. Maybe the warmth will reinvigorate these layers. Or maybe they're just waiting for you to come along and find a shallow point in the snowpack.  Either way, persistent weak layers are inherently difficult to predict, so there is naturally a large degree of uncertainty in how they will respond in the coming days.

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