Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

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

Look for lingering slabs of wind-drifted snow in exposed alpine terrain on Saturday. These avalanches could break in surprising ways if they fail on weak snow just above a crust 1-2 ft below the surface. Shady terrain without wind-stiffened surfaces will have softer snow and safer travel alternatives. 

Avalanche problems

  • Wind Slabs

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

    You'll generally find wind slabs stubborn and tough to trigger on Saturday. However, in some areas, stiff wind slabs formed over weak snow layers that take longer to strengthen, and you could still trigger a large, hard slab avalanche. These are becoming less likely with time, warmer daily temperatures, and cool nights.Consider the high consequences of triggering a wind slab that breaks wider and deeper than expected if it fails on weak snow above the Early February Crust. 

    Common places you'll encounter these wind drifted slabs are on the leeward side of ridges, on the breakover of unsupported slopes, alpine couloirs, and under rock and cliff bands. Hollow-sounding drifts, shooting cracks through stiff or textured surface snow, and the snowpack collapsing under your weight are warnings that you have found unstable wind slabs. Assess recently drifted snow carefully before committing to steep terrain.

    (2/16/2024)

    Small test slopes work great for seeing how reactive shallow wind slabs are. 

    Photo: Julz Holder - Grounding Truth

Avalanche Discussion

Saturday will feature a transition day for the East South. Look for increasing clouds and winds as the day progresses. We have an active weather pattern knocking on the door, so be ready for changing conditions and increasing avalanche danger come Sunday. 

Forecasters were out on Thursday and found weak structure with rounded facets over the stout crust from early February. However weak, the weak layer did show signs of rounding and strengthening. Still, it'll be worth exercising caution in upper elevation terrain with dry snow that appears wind loaded. Stiff wind-textured surfaces can point you to potential wind slab locations. You can also use quick hand pits to feel for stiff over soft snow and observe the bond with underlying crusts. When in doubt, reduce your uncertainty by choosing well supported or more simple terrain. 

Since February 14th, storms have brought 14-16 inches of snow to the East South zone. In much of the region, this new snow now sits over persistent weak layers of faceted snow over the slick Early February Crust (EFC). Observers in many areas of the Cascades, including in an NWAC forecaster in the Darland Mt area last week, have found weak, faceted snow just above the stout EFC crust and also over a thin, breakable crust buried on 2/14 on southerly aspects. This persistent weak layer has produced avalanches in neighboring zones (observation here). Since February 15th, 13 unintentionally human-triggered avalanches have failed on or just above the EFC throughout the Washington Cascades. We have reports of avalanches on all aspects between 5000ft and 8000ft. It has been a number of days since the last reported avalanche, but these problems can be tricky and linger in certain spots like steep, rocky terrain with a shallower snowpack.  

Expect a very thin snowpack at lower elevations and on some steep southerly slopes. Slick crusts, exposed obstacles, open creeks, and bare ground continue to make travel more adventurous. 

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