Avalanche forecast

Banner Summit

Sawtooth Avalanche Center
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Avalanche danger

Wed
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
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Highlights

You're most likely to trigger a large avalanche on steep slopes facing the northern two-thirds of the compass. Watch for and avoid fresh, stiff wind drifts. Choose more conservative terrain if obvious signs of instability, such as cracking or collapsing, are present.

Avalanche problems

  • Loose Dry

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

    Loose snow avalanches: If you're playing in very steep terrain, you could trigger sluffs involving the snow that has fallen over the past few days. Natural loose snow avalanche activity is likely to increase on slopes receiving direct sunshine. Be aware of where a smaller avalanche may take you, and avoid riding in avalanche terrain above terrain traps such as gullies, creeks, and thick timber.

    Wind Slab: Isolated wind slabs up to 2 feet thick formed in recent days. The slabs could rest above weak crust and facet combinations on southerly aspects or small sugary facets on more north-facing slopes - this could make avalanches easier to trigger and wider than you might expect. You're most likely to find the slabs immediately beneath exposed upper elevation ridgelines and on the sides of cross loaded gullies.

    *These new snow avalanches may "step down" into deeper buried weak layers (problem #2) resulting in much larger avalanches.

    (2/15/2025) This natural wind slab avalanche released naturally on Feb 14 or 15 in the Goat Ck drainage. SE aspect near 10,000'. The slide may have been triggered by cornice fall. It appeared to involve the snow that fell on Feb 13-14. 

    Photo: Sawtooth Avalanche Center

  • Persistent Slabs

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

    Although the slabs that formed in early February seem to be stabilizing, they rest above a variety of ugly, widespread, weak layers (facets, surface hoar, crusts, and combinations). Before triggering an avalanche, you may or may not 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:

    • A smaller wind slab or loose snow avalanche overloads the buried weak layers (problem above)
    • 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
    • The slab is less than about 3' thick—relatively shallower spots may exist where the wind frequently blows, and the slab is not uniformly thick.

    (2/17/2025) Sun Mountain E avalanche looking up from the bottom of the debris.

    Photo: Sawtooth Avalanche Center

Avalanche Discussion

We continue to receive reports of relatively stable conditions in the Banner Summit area. Treating freshly wind-loaded or drifted avalanche starting zones with caution is a great move given the recent snowfall and winds. Be aware of where even small avalanches may take you; terrain traps increase the consequence of being caught or buried.

Regions covered