Avalanche forecast

Banner Summit

Sawtooth Avalanche Center
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Avalanche danger

Sun
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Out of date — this forecast expired 2 years ago.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

The snowpack is generally stable, and triggering a large avalanche is unlikely. If you were to find trouble, it would be on the northern two-thirds of the compass in steep, rocky, alpine cirques. 

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Unlikely
    Size
    2–2.5

    Slabs that formed in early February rest above a variety of ugly, widespread, weak layers (facets, surface hoar, crusts, and combinations). Before triggering an avalanche, you're unlikely to experience obvious signs of instability like snowpack cracking and collapsing or whumpfing. Persistent Slabs can release in surprising ways and break much wider than expected. You are most likely to trigger a dense, 2-4 foot thick avalanche where:

    • The snowpack is less than about 4 feet thick—relatively shallower spots may exist where the wind frequently blows, and the slab is not uniformly thick.
    • Any part of the slope you are on or connected to is steeper than about 35 degrees
    • The slope faces the northern 2/3 of the compass
    • A smaller wind slab or loose snow avalanche overloads the buried weak layers

    (2/17/2025) Avalanche on Sun Mountain in a thin snowpack near Ketchum.  Photo: Sawtooth Avalanche Center

Avalanche Discussion

Conditions are generally stable in the Banner Summit area, and triggering a large persistent slab avalanche is unlikely. On Thursday, near Cape Horn summit we found a deep and generally stable snowpack, further building confidence in the low likelihood of triggering a large, thick avalanche. If you were to find trouble it would be in shady, rocky, alpine cirques where the wind frequently blows and the snowpack depth is variable.

You may find lingering small wind slabs or dry surface snow capable of producing sluffs in isolated, very steep terrain approaching 40 degrees in steepness. While they shouldn't be large enough to bury a person, they could knock you off your feet and take you for a ride. 

You can hedge your bets when traveling in avalanche terrain by skiing and riding slopes one at a time and choosing terrain free of terrain traps (i.e., cliffs, gullies, and thick tree stands).

Regions covered