Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Highlights

Another round of light snow and continued winds may form shallow slabs where you could trigger an avalanche. If you identify stiff textured snow or deep pillow-like drifts, steer around steep slopes. A low likelihood but high consequence chance of triggering a much larger avalanche on weak snow 2-4ft deep also exists, so consider this potential if you are stepping into steep, northern terrain at upper elevations.

Avalanche problems

  • Wind Slabs

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

    At upper elevations, continued winds and some light new snow may form shallow fresh wind slabs where you could trigger an avalanche. Older wind slabs that formed on Sunday and Monday could still be lingering and might be covered by a dusting of fresh snow. Slopes below ridgelines and the base of cliffs are likely spots for wind slabs to form. Look for textured surfaces or stiff, hollow-sounding snow to identify wind slab locations. You can also use quick hand pits, your probe, or poles to feel for stiffer snow over softer snow. If you see shooting cracks in wind-stiffened snow, this is a sign to choose low-angle terrain. Cornice falls are common this time of year and are a hazard on their own, but they can also trigger slab avalanches on the slopes below. Don't linger for long beneath these monsters. We expect most of these avalanches to be small, but there is potential for these avalanches to step down into deeper layers and become large. 

    (3/18/2022)

    An example of a small wind slab below a corniced ridge.

    Photo: Andrew Kiefer

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–3

    While we think the potential for widely propagating persistent slab avalanches is isolated, it can still be challenging to identify which slopes have the potential for avalanches on these weak layers. While the likelihood is low, the consequences of triggering a 2-4ft thick avalanche could be dire. You'll want to consider these risks before jumping into steep north-facing terrain at upper elevations. If you travel in this terrain, choose well-supported slopes and avoid likely trigger points like shallow spots near rocks and trees or steep convex rollovers. 

    We have observed a preserved weak snowpack structure of faceted snow over the Early February Crust on some northern aspects above about 5500ft. Stability test results are inconsistent, and this layer has had little avalanche activity since the warm-up. We can't write this tricky problem off yet, but we're gaining confidence that it's much more difficult to trigger. 

    These avalanches can be surprising, propagating widely or getting triggered from a distance. You may or may not see any signs of instability before triggering this type of avalanche. The best way to reduce your risk of triggering one is by avoiding steep, rocky, wind-swept terrain on the north side of the compass. 

    (3/6/2024)

    Steep, shady, wind-loaded terrain is the type of terrain that the persistent problem could plague. 

    Photo: Anthony Lubetski

Avalanche Discussion

There might be some light rain and snow showers in the morning but expect sunnier skies in the afternoon. Further west towards the Cascade Crest, there will likely be heavier precipitation. As the sun warms up southern slopes in the afternoon, you may see some small wet loose avalanches or rollerballs. 

 It is early spring, and the dynamic spring weather brings dynamic avalanche conditions. New snow concerns like wind and storm slabs can quickly become wet snow problems by the afternoon. Make frequent observations, and be prepared for rapidly changing conditions and snow stability. 

This past system favored the east slopes of the Cascades. Weather stations across the zone picked up around 6-12 inches of new snow above about 5000ft, with rain below. Observers in neighboring zones reported wet snow easily shedding and even small storm slabs releasing. I was in the Ahtanum/Darland Mt area last Tuesday. The prolonged period of sun and warm temperatures had done a number on the lower elevation snowpack and steeper southerly slopes. The snowpack on southerly aspects was wet and moist to the ground but more supportable than other sunny aspects where you could punch through wet snow to your waist. Northerly aspects held a colder, more layered snowpack, with preserved weak snow over the early February crust about 4' down on a north aspect @ 6700'. 

Observations have been sparse. Help create a more accurate forecast by submitting your public observations here. 

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