Avalanche forecast

Banner Summit

Sawtooth Avalanche Center
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Avalanche danger

Thu
Alpine
2 · Moderate
Treeline
1 · Low
Below
1 · Low
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Highlights

You are most likely to trigger avalanches where the wind has formed drifts or stiffened the snow surface. The fresh slabs are largest and most widespread in upper-elevation terrain.

Avalanche problems

  • Wind Slabs

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

    What is it? You could find fresh wind slabs up to about 18" thick in exposed terrain. Yesterday, we observed several natural avalanches near Smiley Creek (photo to right/above) and one just above the road on Galena Summit (photo below). The erratic, W-NW-N-NE winds of the past 36 hours may have formed both soft and stiff slabs. Wind slabs could overlie weak facets or crusts on SE-S-SW aspects or a thin rain crust that formed Monday; these slabs will be more sensitive to triggering than you might expect. Due to the hard crusts beneath the recent snowfall on more southerly-facing slopes, even small avalanches could run farther and faster than anticipated. 

    Where is it? Look for wind-blown snow below exposed ridgelines, on the sides of gullies or chutes, and near large terrain features. Wind slabs will be thickest, widest, and most common at upper elevations.   

    How can you recognize it? Cracks shooting out from your skis or sled are an obvious sign of instability. Watch for drifts, dunes, and ripples on the snow surface. Wind slabs can have a smooth, chalky appearance and feel and sound hollow, like a drum. Wind-deposited snow will be stiffer and keep your skis or snowmobile on or closer to the surface.       

    How can you manage it? Managing this problem is simple; steer clear of recent wind drifts and slabs on slopes steeper than about 35 degrees. Stiffer slabs that keep you or your sled on the snow surface can behave unpredictably, breaking above skiers and riders. 

    (2/21/23) These wind slab and loose snow avalanches released naturally on E aspects near 10,000' in the Smiley Ck drainage, likely on Tuesday, Feb 21st. 

Avalanche Discussion

Steering clear of recently formed drifts and slabs is the most effective way to stay out of trouble today. While minor, there is one other scenario to keep in mind as you prepare to head into the mountains:

  • Loose snow avalanches: The mountains received several inches of low-density snowfall yesterday and could see more of the same this afternoon. Also, the upper foot of the snowpack is extremely weak and faceted on some NW-N-NE-E facing slopes. On very steep slopes approaching 40 degrees, it won't take much to get surficial sluffs moving (photo). A little bit of direct sunshine, new snowfall, or some wind-blown snow sifting onto a steep slope could trigger natural loose snow avalanches. These probably won't be big enough to bury you, but they can pack a punch and could knock you over, pushing you where you don't want to go. Sluffs have the potential to trigger wind slab avalanches when recent winds formed stiff drifts lower in cirques.  

Pay attention to the terrain above you. Even small avalanches can ruin your day in complex, high-consequence terrain. Before committing to skiing or riding that steep, beautiful-looking line, think about where an avalanche could carry you. Could you get pushed over cliffs, through trees, or into a creek or gully? Slopes with these terrain traps are inherently more dangerous than open slopes with a clean runout. 

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