Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1–2
Wind slab avalanches up to 1' deep will be easier to trigger on steep wind loaded slopes above 2,500’. A recent large avalanche was observed on John Mtn. It was hard to make out what type of avalanche it was. It likely started as a wind slab and may have entrained wet snow as it ran to lower elevations. On some slopes there may be a wind slab sitting over a layer of buried surface hoar or facets that will make these easier to trigger. What will be tricky today is locating and avoiding terrain with "more reactive" weak layers. Traveling tests may produce stable results but the slope you ride may have pockets of weak layers that are hard to find. Recent avalanches are great clues as well as taking the time to conduct more traveling tests such as hand shear tests and testing small, safe slopes to see if they create an avalanche. Utilizing safe zones and exposing one person at a time on a slope will increase your margin of safety.
Above freezing temperatures and rain will make it easy to trigger a wet loose avalanche below 1000’. A group on Tincan triggered wet loose avalanches yesterday in the trees. Watch out for these as they can carry someone over a cliff or into trees. Dry loose avalanches may sweep you off your feet in steep wind sheltered terrrain.
Glide Avalanches: Warm springlike temperatures typically increase glide avalanche activity. We have seen some glide cracks slowly opening on the south end of Seattle Ridge. Keep your head up as you move through valleys and try to avoid spending time under these whenever possible.
Cornices: Cornices have grown very large on some ridgetops in the forecast zone. Recent winds, new snow, and warm temps will be making these more sensitive to trigger. Avoid traveling under cornices and be mindful of them if you find yourself on a ridge today.
(2/20/2025)
Wind transporting snow throughout the day.
Photo: Mik Dalpes
