Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Possible
- Size
- 1
Winds are starting to increase as of early this morning, gusting NE 15-20 mph on Marmot 4500' and E 20-28 mph on Hatch 4561'. Winds are expected to increase throughout the day, with the strongest gusts expected this afternoon through Sunday. By the end of the day, expect wind slabs 3-6" thick to be possible to human trigger on south to northwest (clockwise) aspects above 3500' on slopes 35 degrees and steeper. Due to the limited duration and intensity of the wind combined with the density of the snow, we expect wind slabs to be isolated to ridgeline and upper elevation. That being said, a significant amount of low density snow exists and is available for transport, especially on leeward or northerly aspects. Due to the uncertainty that exists with the duration and intensity of the wind forecast, we could see smaller or thicker slabs. Pay attention to obvious clues of wind loading.
Use hand pits and pole probes to identify wind slabs. Look for hard snow sitting over weaker snow, smooth and rounded or lens shaped features. Shooting cracks or whumping are signs of instability and indicators of this avalanche problem.
As always, we recommend carrying the appropriate rescue gear and knowing how to use it. Safe travel techniques are important every time we travel in avalanche terrain. This means spreading out when ascending slopes, descending one at a time, and regrouping well outside of the run out zone.
PERSISTENT SLAB
Expect to find lingering, persistent slabs up to 3 feet deep in isolated and extreme terrain above 3500' today. Triggering a slab today will be unlikely as this problem trends from stubborn to unreactive. However, we continue to see the persistent slab rear its head in isolated locations like Hidden Bowl on the 17th. Although we continue to find poor snowpack structure in some locations that is contributing to this problem, the slab/weak layer continuity is hard to find in most locations, which will reduce the likelihood of triggering an avalanche. Today's wind forecast is not expected to contribute to the persistent slab problem.