Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Slabs of wind-blown snow have formed in exposed middle and upper elevation terrain. 6 inches of new snow overnight and moderate SW winds may keep wind slabs reactive to a human's weight, especially if they break buried weak layers above the 2/7 crust. Most of these slabs will likely be on the smaller side, but I wouldn’t rule out the potential for a large avalanche in heavily drifted terrain.
These wind-loaded areas will be most prevalent on the leeward sides of ridges and moraines, below cornices, and beneath rock and cliff bands. With over 6 inches of new snow, triggering avalanches in more sheltered terrain is not out of the question, especially in areas where new snow may sit over surface hoar or near-surface facets.
Winds are forecast to decrease through the day, so use surface clues like ripples, dunes, and sharp drifts to help you identify nearby wind-loaded terrain. Shooting cracks or whumphs are obvious clues that you found an unstable slab. You can easily reduce your exposure to this problem by sticking to ridges or more sheltered terrain under 30 degrees.
Additional Discussion: There is some uncertainty regarding cloud cover. If the sun decides to poke out, be mindful of wet loose instabilities on steep sun-exposed terrain. Look for rollerballs and pinwheels as indicators that the surface snow is becoming wet and weak.
(3/31/2025)
Ripples and cornices like this will help you pinpoint where wind slabs may exist.
Photo: Joe Dellaporta