Bulletin d’avalanche

East Slopes South

Northwest Avalanche Center
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Danger d’avalanche

Sat
Alpin
2 · Modéré
Limite forestière
1 · Faible
Sous la limite
1 · Faible
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Périmé — ce bulletin a expiré 3 years ago. Vous consultez des conditions passées, pas le bulletin en cours.

Points saillants

There are only isolated areas with enough snow, but avalanches may be easy to trigger as new snow builds up on weak or icy surfaces. The most suspect areas are shady high-elevation slopes and wind-drifted slopes near ridges. Rocks, creeks, and other hidden obstacles can increase the consequences of an avalanche.

Problèmes avalancheux

  • Wind Slabs

    • Alpin
    • Limite forestière
    • Sous la limite forestière
    Probabilité
    Possible
    Taille
    1–1.5

    You may be able to easily trigger wind slabs that form over weak or icy surfaces. Winds will likely pick up into the moderate range in the morning on Friday and drift the new low-density snow into stiff slabs. Avoid steep slopes if you observe shooting cracks or feel the snow collapse beneath you. While these avalanches are not expected to be large, even a small avalanche could drag you through exposed rocks or creeks.We don't have direct observations from East South yet. But, in adjacent zones, wind-loaded terrain at higher elevations currently holds the most snow. These high elevations will be the most likely place to trigger an avalanche. However, shady, steep, open slopes sheltered from the wind, such as gladed forested areas, may harbor weak snow surfaces. These slopes may be far and few between, but you could trigger a storm slab if you found the right spot. Monitor the snowpack beneath you frequently as you move through the terrain. Stick to low angle slopes if you dig down and see large, feathery surface hoar or weak, sugary snow. 

    (11/21/2023)

    EXAMPLE: Blowing snow and pillow-like drifts are good ways to identify wind-loaded terrain. 

    Photo: Matt Primomo

Avalanche Discussion

We're kicking off the daily forecast season to welcome in a much-anticipated storm for this upcoming weekend. 

We are starting with a very weak and thin snowpack on the east slopes of the Cascades, and most lower elevations are still bare ground. While we don't have on the ground observations yet from East South in adjacent zones snow becomes continuous at around 5000ft in the eastern portion of the zone. At higher elevations, areas further west in the zone have about twice as much snow. Over the last week, I found 35cm at 5200ft in Icicle Creek and 50cm of snow at similar elevations in Salmon La Sac. In most locations, the west and south aspects are nearly bare ground up to around 6000ft. Shady slopes hold weak snow covered with large surface hoar crystals that may be prone to avalanches under this new snow load. Sunny slopes have patchy snow cover or icy crusts that make a good sliding surface for avalanches. 

With the highly variable nature of the current snowpack, it can be tricky to identify which slopes are more likely to avalanche. Adjacent slopes may act differently from each other, so here are a few tips to track what's happening beneath you as you travel.

  • Dig down frequently as you travel. This is particularly important as you change aspects and climb in elevation. 
  • Use your probe or pole to track snow depths and identify areas of thin snow cover where hidden obstacles may lurk. 
  • Use quick hand pits to observe how well the new snow bonds to the old surface. If it slides easily, avalanches are more likely. 

You can expect snowfall throughout the day on Friday. So avalanche problems could worsen by late afternoon. The new snow will be relatively low density and may not readily form a slab. Therefore, you may see some long-running loose snow avalanches. Small avalanches or just traveling in these low-tide, early-season conditions hold high consequences if you impact rocks or other hazards. So, move slowly and cautiously in the mountains until more snow builds up. 

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