Avalanche forecast

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Northwest Avalanche Center
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Avalanche danger

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

We've got a tricky, unstable snowpack, and taking a step back to lower-angle terrain is the best way to avoid avalanches. On wind-drifted slopes, avalanches could be much larger and break across terrain features. Avoid steep wind-drifted slopes below ridgelines and pay attention to warning signs, such as cracking and collapsing, that let you know steep slopes are dangerous. 

Avalanche problems

  • Persistent Slabs

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

    7-10" of snow fell over weak faceted snow and buried surface hoar. Moderate to strong winds will put additional strain on these weak layers as large wind slabs form on lee aspects below ridgelines. In these wind-loaded areas, avalanches may break widely across terrain features or be triggered remotely. You'll want to steer clear of steep lee slopes near ridgelines, where these avalanches are likely to be much larger. On sheltered slopes, these avalanches may act more like your average storm slab, but they may be reactive for longer than you expect.

    Long shooting cracks, whumping collapses, or natural avalanches are key indicators of dangerous avalanche conditions. Small, steep test slopes or convex features can help gauge the reactivity of the upper snowpack. But given snowpack variability, be cautious about extrapolating your results too broadly.  Instead, seek out low-angle terrain protected from the wind while the snowpack adjusts and we gain more information on how the buried persistent weak layers are handling the new load. 

    Natural slab avalanche with wide propagation in the Hairpin Valley. We suspect this avalanche failed within weak snow over the 2/7 crust. SS-R2-D1.5

  • Loose Wet

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    The sun is expected on Wednesday, particularly in the eastern portions of the zone. With plenty of fresh snow over slick crusts, wet avalanches might start rolling down steep sunny slopes. These avalanches might start naturally from trees and rocks shedding snow or be triggered by traveling in steep terrain. Rollerballs and heavy, wet snow are the first signs of this avalanche problem. As sunny slopes heat up, consider moving to lower-angle or shady slopes. 

    (2/7/2025)

    An example of natural loose dry avalanches from last season near Washington Pass.

    Photo: NCH

Avalanche Discussion

There should be intermittent cloud cover on Wednesday, with a better chance of full sun farther east in the zone. The combination of warming, sunshine, and windy conditions won't be a good combination with our unfortunately poor snowpack structure. Stay diligent with your observations and give yourself greater margins of safety to avoid getting surprised. 

Over the past few days, a widespread cycle of natural and triggered avalanches in the Washington Pass area has been reported. A decent share of these are confirmed to have run within weak, faceted snow over the 2/7 crust. While most avalanches were small, we have limited information from wind-loaded terrain. Over the weekend, there was a report of a widely propagating, but shallow wind slab avalanche near Heather Pass. While we don't have much info on that incident, the propagation is a clear warning sign of persistent slab avalanches. There is uncertainty about the extent of avalanches these persistent weak layers will produce, but it's best to treat them with suspicion until they prove otherwise. 

On all but southerly aspects, there's 8-12" of dry, weak snow over the upper crust (February 7th). The layer immediately above the crust is very weak with larger faceted grains and surface hoar. The January 28th crust is thicker and now 12-16" below the surface.  On southerly aspects, there are more crusts and less dry, weak snow on the surface. Further west of Washington Pass, the crust may be thicker and deeper with more dry snow between them. Farther east, in places like the Chewuch and Twisp River drainages, the snowpack is shallower and weaker. Here, the crusts have become faceted on shady aspects, with the upper 2/7 crust barely discernible in some northerly terrain.

Regions covered