Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–1.5
On Friday morning at the start of my ski tour, there were two things that immediately stood out to me: stronger than forecasted winds and snow actively blowing off ridgelines. As the day went on, those SW winds did not subside and were consistently on the upper end of moderate with strong gusts. This resulted in significantly wind affected snow surfaces, and I observed a widespread wind crust on mid and lower slopes in the Broken Top bowl on all but west aspects, which were scoured. Wind slabs are most likely to be lurking at the upper elevations of above treeline terrain. Despite observations and stability test results showing good bonding of new snow to the old snow interface, the poor structure is there, of strong snow on top of weak snow (i.e. a slab).
Saturday is looking to have very light winds and relatively warm air temps. With this, I would expect wind slabs to stabilize relatively quickly and the problem to trend downward as the day progresses. Most slabs will trigger above the old snow interface (crust on east, south, west, drier snow on sheltered norths) and be on the small side. However, with a few inches of recent storm snow at our upper elevations, you could find pockets of larger slabs of 1' depth or greater. As you move through terrain, use snowpack tests and non-consequential test slopes to gather information on potential slab reactivity. Shooting cracks are one of the most obvious warning signs that the slope you are on (and/or similar slopes) could avalanche. If in doubt, seek lower elevation terrain, windward slopes, or slopes less than 30 degrees.
(1/30/2026)
Snow blowing off ridge and loading upper slopes on Broken Top. It is easy to also see the wind affected surface snow on middle and lower sections of the slope
Photo: Ryan Marvin