Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

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

The stormy weather pattern is taking a break, but you could still trigger avalanches where stiff wind drifted snow rests over weak surfaces. These avalanches could step down to more deeply buried weak layers, becoming very large and breaking across terrain features. Choose lower angle or sheltered terrain to avoid triggering one of these surprising avalanches. 

Avalanche problems

  • Wind Slabs

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

    Warming temperatures helped the storm slabs settle and become more stubborn. But wind slabs that formed over old weak surfaces can take longer to heal and could still be reactive, particularly at upper elevations. In many areas, the new snow rests on weak facets or surface hoar. Telling exactly what slopes will harbor these lurking instabilities will be very challenging. But you're most likely to trigger avalanches below the lee side of ridgelines, the base of cliffs, or confined terrain features.

    Use visual clues to identify wind-loaded terrain, such as cornices or drifts around rocks and trees. Look for signs of instability, like recent avalanches or shooting cracks, as a warning to stick to lower-angle terrain. Seek out sheltered terrain to reduce your likelihood of a small wind slab stepping down to deeper layers and triggering a surprisingly large avalanche. 

    (2/28/2023)

    Look for pillow-like slabs, dunes, and wind textured snow to help you identify slopes of concern. 

    Photo: Katie Warren

  • Persistent Slabs

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

    We know very little about the persistent slab problem in the East South. However, previous avalanche activity in this zone on persistent layers, very large avalanches as recently as Friday in West South, and avalanches to the north (East Central) make it a good bet this tricky problem also exists here. All this recent snow could be the tipping point for the deeper instabilities. 

    Weak facets exist on and within several crust layers buried deep in the snowpack. Before the storm earlier this week, multiple groups triggered small slabs on a buried surface hoar layer (1/2). These avalanches could now be 2-4ft deep! These persistent problems take prolonged patience, so as we exit this very active weather pattern, step out into new terrain slowly and cautiously. 

    A smaller storm slab, cornice failure, or just hitting the wrong spot could cause the entire slope to slide. Sure, you're more likely to trigger a storm or wind slab, but the consequences of one of those stepping down to one of these deeper persistent weak layers could be unsurvivable. Talk about this issue before you set foot in any part (start zone, track, or runout) of avalanche terrain.

    (1/14/2024)

    This widely propagating avalanche occurred near Sourdough Gap/Morris Creek near the boarder of the West and East South zones. 

    Photo: Dan Royal

Avalanche Discussion

Areas closer to the Cascade Crest may have gotten rain or freezing rain on Friday, putting an icy lense over the snow surface. The distribution of the mixed precipitation types is hard to pin down, but it may make some areas more or less likely to have lingering avalanche concerns. We've just gone through a big transition back to wetter and warmer weather. As we step out into the mountains after these big shifts, be prepared to make assessments as you travel, and don't be surprised to see strange or quickly changing conditions. Speaking of wetter and warmer, you may see a few rollerballs or small wet loose avalanches in steep terrain on Saturday. If the sun comes out, these could be a bit more widespread, but we don't think it will become a problem. We haven't had much recent info from East South since last weekend. But on Thursday in East Central, widespread sensitive storm slabs failed on the 1/16 interface of weak faceted snow. White Pass Ski Patrol reported a few natural avalanches failing on the recent 1/16 interface on Friday. An NWAC forecaster at Crystal Mountain saw a suspiciously large avalanche in Morse Creek, very close to the border of East South. With big avalanches and a lot of uncertainty, it's always a good idea to step into new terrain slowly. 

Regions covered