Avalanche forecast

West Slopes South

Northwest Avalanche Center
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Avalanche danger

Fri
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

Slabs of wind-drifted snow should be on your radar tomorrow. Look for areas of wind loading from the past storm and also with continued moderate winds. Warmer temperatures and more sunshine are in store so there is a greater chance of seeing wet avalanches on southern aspects. 

Avalanche problems

  • Wind Slabs

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

    Additional snowfall and strong winds overnight into Wednesday morning built fresh wind slabs and even spurred a round of small natural avalanches. These slabs will likely be more difficult to trigger but you could still find one if you venture onto steep, unsupported slopes. Winds are not forecast as strong but could still be enough to facilitate additional wind transport and build fresher, more sensitive slabs.

    Wind-loaded slopes can be identified by the usual signs like scoured ridgelines, fresh cornices, and other wind-drifted features. Wind direction could vary so signs of loading from Wednesday may get undone if the wind takes a more easterly track tomorrow. Carefully assess steep wind-loaded slopes, especially just below ridgeline. The best bet is to just navigate around the steepest features on lower angle terrain. Slopes seeing active wind loading are where you are more likely to trigger an avalanche.

    (2/8/2023)

    Natural slab avalanche in Union Basin. E aspect @ 6350'. Likely released with wind loading early Wednesday morning. The crown is visible below the lowest ridgeline on the left.

    Photo: Shane Robinson - Graybird Guiding

  • Loose Wet

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

    There is no shortage of fresh, new snow in the Cascades. Warmer temperatures and stronger sun are forecast for Thursday so, wet loose avalanche activity might consist of more than a few rollerballs. It's not guaranteed you will see anything significant. Still, stay alert to steep slopes overhead as the sun comes out.

    Look for initial signs of instability like snow shedding from trees and rocks. Pinwheels or balls of snow rolling down the slope are also telltale signs of warming. If you see these it would be a great time to give a wide berth to slopes that face the sun. Though initially small, wet avalanches could grow in size or trigger a slab avalanche lower on the hill and run farther than expected.

    Natural rollerballs, loose wet, and small wet slab avalanches in early January.

    Photo: Dallas Glass

Avalanche Discussion

All in all, Thursday will be a bit of a transition day for the mountain snowpack. After several days of stormy weather, the new snow loads will finally be about 24 hrs old. Sometimes these situations can get tricky as lingering storm snow issues become less prevalent, but avalanche concerns remain. Combine that with some mild temperatures and blue sky, and the draw to step into bigger terrain can be palpable. Right now we're primarily worried about the new snow since Friday (2/3). This interface can be found 15-30in (45-90cm) below the snow surface. When we're talking about layers that deep, little hand pits and small slopes may not provide you with all the information you need. Consider easing into terrain by starting with smaller and lower consequence slopes before stepping into larger avalanche paths. 

On Friday avalanche professionals at Crystal Mt reported several fresh natural slab avalanches primarily in wind loaded areas below cornices and cliffs. As the storm ended and the skies began to clear, rollerballs and a few small loose wet slides were also observed. While there was plenty of sunshine, skies did not completely clear. As a result, a new patchy sun crust may have formed on some steep southerly slopes. This also means that the post-storm loose wet cycle may not have completely run it's course. 

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