Avalanche forecast

East Slopes Central

Northwest Avalanche Center
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Avalanche danger

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

You could trigger avalanches in recent snow on steep terrain, especially in western areas of the zone with higher snow totals. Avalanches could be larger if they fail on deeper weak layers or where winds drift snow deeper. Consider lower-angle terrain where you find more than 6 inches of new snow, and avoid steep slopes with deep drifts. 

Avalanche problems

  • Storm Slabs

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

    Cracking, collapsing, or recent avalanches are clear indicators that storm slabs are still reactive. You are most likely to trigger a storm slab in areas further west in the zone, where more snow accumulated on Sunday. Other likely places to trigger an avalanche are wind-loaded lee slopes below corniced ridgelines.

    Choose lower-angle terrain at upper elevations, avoiding steep slopes with deep wind drifts. At lower elevations, default to simple, conservative terrain and avoid likely trigger points such as steep convex rollovers. You can use quick tests to see how the recent snow reacts. Hand pits that produce clean, easy shears and or test slopes that produce mini avalanches or shooting cracks are all signs you could trigger an avalanche on a steep slope. It's also important to keep in mind that the recent snow fell on inconsistent and variable surfaces, so a test slope result in one area may not be applicable to another nearby slope.

    (12/1/2023)

    An example of a test slope showing unstable snow. 

    Photo: Matt Primomo

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1.5–2

    We aren't sure if the modest precipitation amounts were enough to increase the likelihood of this tricky avalanche problem. However, sometimes, small inputs can significantly impact weak snow layers. With the additional snow, wind, and warming temperatures, take time and let our weak and variable snowpack adjust to the changing conditions. This is a low-likelihood, high-consequence situation. While you'd be unlucky to find just the right spot for triggering one of these avalanches, the subsequent avalanche could take you for a nasty ride and/or fully bury you. With persistent slab problems, you may or may not observe signs of instability before triggering an avalanche. The safest travel choice is simply to avoid steep north-facing terrain, particularly on wind-loaded slopes below ridgelines or the base of cliffs.

    You can dig down and identify the weak, sugary snow layers 1-2ft below the recent snow and see how they react in snow stability tests. But, with persistent slab problems, you may or may not observe signs of instability before triggering an avalanche. The safest travel choice is simply to avoid steep northerly terrain, particularly on wind-loaded slopes below ridgelines or the base of cliffs.

    (2/14/2025)

    You can clearly see the grey-ish line of weak facets in the wall behind the failed snowpack test. These weak grains aren't hiding, they're easy to spot. 

    Photo: Dallas Glass

Avalanche Discussion

Areas close to the Cascade Crest picked up 5-7 inches of snow on Sunday, with less than 4 inches in the eastern part of the zone. Winds weren't very strong with the storm, but they'll continue transporting our low-density snow along ridgelines at higher elevations. With continued warming temperatures on Monday, you might see some rollerballs or small, wet loose avalanches at lower elevations, especially in western areas like Salmon La Sac. 

Mission Ridge Ski Patrol reported a small, natural wind slab on Sunday, likely triggered by a cornice fall outside the ski area boundary. Observers in the Blewett Pass region found 4-6 inches of snow over slick crusts with some wind affect and minimal signs of instability. 

Since the onset of the persistent slab problem, the East Central zone has not seen a significant number of signs of instability. There have been no confirmed persistent slab avalanches up until this point. Although the January Drought Layer (JDL) was and still is pervasive, the problem lacked a cohesive and deep enough slab a lot of areas. Now, that slab will be considerably more settled and will be getting compressed by new snow. With just a few more inches of "seasonably dense" new snow, will this be when we see a more widespread avalanche cycle? Time will tell...

Although we aren't telling you that travel in avalanche terrain is not recommended, it should be clear by now that managing Sunday's avalanche hazard is complex. We do recommend that you keep your tour plan simple to have a more enjoyable day in the backcountry.

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