Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
1 · Low
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Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You could still trigger an avalanche in weak snow lingering beneath new snow and wind slab layers from last weekend’s storm. Don’t ignore obvious signs of instability like recent avalanches, whumphs, or shooting cracks. Approach new terrain slowly and assess conditions as you gain elevation. 

Avalanche problems

  • Persistent Slabs

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

    The snowpack structure in many areas is weak, especially where a slab of stiffer, more recent snow sits on softer, weaker snow below. Steep, northerly aspects are where you are most likely to find this type of layering - and trigger and avalanche - but be on the lookout anywhere there is enough snow to cover ground features. Use extra caution on sparsely vegetated slopes, steep terrain below ridges, convex breakovers, and around rocks or cliffs where you are more likely to trigger these avalanches. 

    You can use snowpits to identify and test areas where sugar-like facets or feathery surface hoar layers have a denser slab above. You might even just be able to dig down with your hand to find the same layering. When in doubt simply default to lower angled, simpler terrain to reduce the risk of triggering an avalanche.

    (12/15/2022) This layer of buried surface hoar on Mt. hood was easily identifiable as a thin gray line 30-50 cm below the snow surface. Similar layering exists in parts of East South Photo: Joe Dellaporta

Avalanche Discussion

No avalanches related to buried weak layers - natural or human triggered - have been reported from East South. A number of avalanches involving similar weak layers were reported from adjoining zones on both the east and west sides of the Cascade Crest in the last week. 

While storm and wind slab layers gain oftentimes strength (and avalanches become difficult to trigger) a few days after being laid down by a storm or wind loading event, layers of persistent weak snow like buried surface hoar and facets take longer to gain strength. Weak snowpacks just need more time to adjust to a new snow load. When another storm rolls into the mountains we might even see avalanches breaking down onto these older layers again under more load.

Most sun exposed terrain has a melt freeze crust on the surface. Valley clouds in the morning may burn off in the afternoon or not reach higher elevations. If you find yourself under blue skies, note that snow on steep, southern aspects may get heavy and wet. You could see roller balls or wet snow sliding off steep terrain near rocks or cliffs. Stay out from under cliffs or rock faces that begin to shed snow. 

If you get out into the East-South Zone, tell us what you see by submitting an observation on our public observation platform!

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