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—especially on SE-S-SW aspects—and 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. In the Sawtooth Mtns, you could find slabs below large cliff bands and on the aprons of chutes and couloirs.
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.