Avalanche forecast

Banner Summit

Sawtooth Avalanche Center
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Avalanche danger

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Out of date — this forecast expired 2 years ago.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

Highlights

Generally stable avalanche conditions exist, and you may need a bit of bad luck to trigger large avalanches. There's a lingering chance of triggering a large slide in steep, rocky terrain where the wind has drifted or stiffened the snow surface. Small, loose snow avalanches are possible on very steep slopes that face the sun.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2

    It is unlikely that you could trigger a dense, 2-5 foot thick slab avalanche. You may still find this problem in isolated areas on slopes facing the northern half of the compass, where the wind frequently blows, and the snowpack depth is variable. Some visual clues to identify suspect slopes:

    • Cornices, wind-pillows, and textured surfaces indicate the wind has been at work.  
    • If you see rocks sticking out of the snow, expect variable snowpack depths. Avalanches are easier to trigger in thin spots at the edges of slabs, near ridgelines, and along rocky, mid-slope ribs.

    Additional discussion: On very steep, sun-exposed southerly slopes that are sheltered from the wind, small loose snow avalanches may occur and could release naturally. Pay attention to the terrain above you. 

Avalanche Discussion

Avalanches will be difficult to trigger in many areas across this zone, especially where mid-December weak layers are buried more than about 3 feet deep. Yesterday, Ethan and I rode near the border of the Banner zone and found a 2-3 foot thick slab of snow above weak layers and no signs of instability. While it is unlikely you could trigger an avalanche in many places across this zone, where you are most likely to find trouble will be in areas where:

  • The wind has drifted or stiffened snow surface—indicated by cornices, ripples, or dunes.
  • Slopes peppered with exposed rocks are a visual clue that thin spots may exist.
  • "Prime-time" avalanche terrain, steeper than about 35 degrees. Triggering a large avalanche is most likely where some part of the slope is at least 35 degrees. 

Regions covered