Avalanche forecast

Banner Summit

Sawtooth Avalanche Center
View on map

Avalanche danger

Sat
Alpine
2 · Moderate
Treeline
2 · Moderate
Below
2 · Moderate
Open full map
Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

You're most likely to trigger an avalanche in areas with stiff drifts or slabs near the snow surface. These slabs have the potential to break down to buried weak layers, causing a very large, destructive avalanche. Loose snow avalanches are possible on very steep slopes that soften in the sun.

Avalanche problems

  • Persistent Slabs

    • Alpine
    • Treeline
    • Below treeline
    Likelihood
    Possible
    Size
    2–3

    Triggering a large, destructive 3-6 foot thick avalanche is possible. These slides will fail on persistent weak layers (crusts, crusts and facets, or facets) in the middle or bottom of the snowpack. You're most likely to trigger one of these beasts in steep, rocky, wind-swept alpine terrain and in the northeastern corner of this zone. Here, thin areas of the snowpack make it easier to trigger avalanches.

    Persistent Slab avalanches can release in surprising ways. You can trigger them from flat or low-angle terrain long distances away from steep slopes, and they can break far above you. They can break hundreds or thousands of feet wide. Before triggering an avalanche, you probably won't experience snowpack collapsing or other obvious signs of instability. 

     

     

    (3/3/2024) The crown of this large avalanche near Valley Ck Lake north of Stanley is an estimated 3-5 feet tall. It probably involved persistent weak layers and failed on a NW-W aspect near 8900'. In the northern mountains, these large persistent avalanches are most likely where the snowpack is thinner: in the eastern side of the Banner Summit zone and the far northeastern corner of the Sawtooth & W Smoky zone (NE of HWY 21). Photo: Sena Strenge

  • Loose Wet

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

    Wet loose avalanches may release on very steep, rocky, wind-sheltered terrain soaking in the sun. These are more likely as the sun softens crusts this afternoon. Pinwheels or herds of rollerballs on a slope indicate the snow surface is softening, and loose snow avalanches may soon follow.

    Most of these slides will be small and relatively harmless; however, large slopes, chutes, and couloirs could produce powerful slides that could easily catch, injure, or bury people. Don't underestimate the power of these slides. Be aware of the terrain above you and where an avalanche could carry you.  

    (3/6/2024) Loose snow avalanches caused by warming from the sun. Photo: Sun Valley Heli Ski

Avalanche Discussion

As skies cleared Wednesday we observed several large to very large avalanches on various aspects in the Sawtooths, Smokys, Boulders, Soldiers, and the mountains around the Wood River Valley (Avalanches). Some of these slides appeared quite crisp, releasing at the tail end of Tuesday's storm. Many broke hundreds to thousands of feet wide, involving one of the multiple weak layers of snow buried in the snowpack. Most of these occurred in wind-drifted, alpine terrain.

Avoiding slopes with stiff drifts or slabs near the snow surface is the best way to reduce your odds of triggering a large avalanche.  As you climb into winder terrain you'll find recently formed wind slabs and variably thinner snowpack areas where triggering a Persistent Slab avalanche is more likely. 

So far, light wind and cool temperatures have kept wet avalanche activity at bay. Today, temperatures will be 5 to 7 degrees warmer with intermittent, calm, and light wind. This may encourage some steep, rocky slopes to shed their recent snow. Avoid lingering beneath these slopes, especially as crusts soften this afternoon.

Regions covered