Avalanche forecast

East Slopes South

Northwest Avalanche Center
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Avalanche danger

Mon
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Out of date — this forecast expired 4 years ago.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

 Light snowfall and moderate west winds will combine to create a fresh batch of shallow wind slabs in exposed areas. It remains possible for you to trigger a larger avalanche on steep upper elevation slopes that face north and east. Steer around steep slopes if you observe shooting cracks, hear whumphs, or see new snow actively wind drifting into deeper pockets. 

 

Avalanche problems

  • Wind Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    1–1.5

    A few inches of new snow and moderate west winds will create a fresh crop of shallow wind slabs in exposed areas. You will most likely find these areas of wind drifted snow at mid and upper elevations, but specifically on the lee sides of ridges, below cornices, and above treeline. These slabs won’t be large, but could be enough to ruin your day. Use visual clues such as looking for where wind is blowing snow to help you locate where potential wind slabs are. 

    (12/3/2022)

    Actively blowing snow, freshly building sharp cornices, and textured surfaces. All easy-to-identify signs of wind-loading. Look for slabs to develop on the slopes on the left side of the picture.

    Photo: Dallas Glass

  • Persistent Slabs

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

    Persistent slab avalanche problems take time to heal. Current observations have been limited across the east-south, however adjacent zones are dealing with a similar snowpack structure.

    Dig down into the snow and look for sugary, weak grains near the bottom of the snowpack from late November or feathery crystals of surface hoar buried 1-2’ below the snow surface.  You can use snowpack tests such as compression tests or extended column tests to locate these possible weak layers.  

    There is some uncertainty with the distribution of these weak layers across the east-south. That being said, the most likely spot you can trigger a large persistent slab avalanche is on higher elevation slopes that face north and east and have been recently wind-loaded. 

    Stick to lower angle terrain if you observe recent avalanche activity, see shooting cracks under your skis/sled, or hear whumphs. 

Avalanche Discussion

Forecasted precipitation amounts are not overly impressive for this storm.  The main story will be the moderate to strong west winds associated with it.  This will bring a small uptick in avalanche hazard, especially in more exposed areas where shallow wind slabs will develop. 

This new snow will be falling on a patchwork of surfaces such as preserved cold snow in sheltered areas (including surface hoar and near-surface facets),  wind affected snow in the alpine, and a sun crust on steep solar aspects.  As new snow piles up, keep an eye on if surface hoar and near-surface facets are getting buried. This weak surface snow could be tomorrow's weak layer.  Hopefully strong winds will help destroy these weak grains before burial, but they’re worth watching as snow continues to pile up throughout the week. 

Observers in the east-south zone are still reporting shallow conditions below treeline. Lots of rocks, stumps, and downed trees are still present. Tread lightly out there!

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

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