Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

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

A storm favoring the east slopes of the Cascades will impact the area overnight on Thursday. Expect new snow, wind, and dangerous avalanche conditions on Friday. Watch for signs of instability, such as shooting cracks or recent avalanches. Travel on low-angle slopes and avoid areas where the wind has drifted snow into deep slabs on lee aspects.

 

Avalanche problems

  • Storm Slabs

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

    This storm isn't typical for the Pacific Northwest, and you can anticipate more snow in areas east of the Cascade Crest. You could trigger storm slab avalanches on steep slopes and convex rolls in the new snow. It will be best to let the storm run its course and stick to low-angle terrain on Friday. Watch for signs of instability, such as shooting cracks or recent avalanches. You can also make observations as you travel using small test slopes and quick hand pits to assess how the new snow reacts. Snow that slides easily in a cohesive block indicates that triggering an avalanche is possible. Moderate winds are also in the forecast, and you should anticipate sensitive wind slabs developing at upper elevations below ridges and in wind-exposed areas. Use visual clues such as textured surfaces, deep pillowlike drifts, or feel for stiff over soft snow layering to identify likely wind slab locations. Wind slabs may be larger and easier to trigger than storm slabs, so avoid steep slopes and potential trigger spots such as the base of cliffs and below corniced ridges. 

    (1/9/2023)

    Storm slabs like this example are likely on Friday. Avoid common trigger spots, like the base of cliffs.

    Photo: Willie Webster

Avalanche Discussion

The East-South zone continues to be in a favorable pattern for daily snowfall. Thursday night's storm packs a bit more of a punch, and 6-10 inches of new snow could fall by the early hours of Friday. There is some uncertainty with this atypical storm track, so be prepared to find greater or lower snow totals than the forecast. During the brunt of the storm, the wind will be primarily from the East before switching around to westerly later on Friday. This pattern means you will likely find wind-drifted snow on all aspects, mainly near and above treeline. Friday will be an excellent day to enjoy the new snow on low-angle slopes sheltered from the wind. 

I was last in the Ahtanum Meadows area on February 28th, and I found 7-12 inches of new snow over the most recent crust from Valentine's Day. There was some weak snow below the Valentine's Crust, but snowpack tests yielded unremarkable results. This crust and the associated weaker snow are likely now 2-3ft below the snow surface. While we expect most avalanches to involve just the recent snow, we are still tracking this deeply buried interface as storms incrementally load it. So far, we have not observed any avalanche activity on this layer, but keep this interface in mind with this storm overnight on Thursday. It is unlikely, but we could begin to see avalanche activity on this more deeply buried crust. 

 

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