Wind Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Likely
- Dimensione
- 1.5–3
Recent Avalanches: We have not heard of avalanches after Friday's storm which could be because few people were in the backcountry to report activity. On Wednesday evening multiple avalanches were remotely triggered on the back side of Seattle Ridge. A significant natural avalanche cycle occurred in Portage Valley including a scary description in Byron Valley.
The arriving storm is expected to bring 3 to 6” snow (Portage may see 12” snow) and moderate east winds averaging 10 to 30 mph which should increase through the day. Fresh wind slabs 1 to 2’ deep will be forming below ridgelines, in gullies, and on convex terrain features. There is also a chance of triggering an older wind slab up to 3’ deep that formed during Friday's storm where 1 to 2’ of snow fell and east winds reached 100 mph. An avalanche this size could trigger a deeper weak layer releasing a much larger avalanche.
Conditions are dangerous today. Blowing snow, shooting cracks, and collapsing snow are all red flags that the snow is being stressed and still needs time to adjust. Approach steep terrain with caution and consider conservative decisions like choosing lower angle slopes.
Cornices were already failing before the storm on Friday which added more stress to these snowy waves. A falling cornice will likely trigger a large avalanche. These form on ridgelines so be sure you are not standing on one and try to limit time spent under them.
Wet snow avalanches could be easy to trigger on slopes where the snow is warm and wet. Wet loose avalanches may increase in size, carry you into trees or gullies, and have the potential to trigger a larger avalanche. This is also the time of year to watch out for wet slab avalanches. Sinking up to your shins is a clear sign that the snow is weak and capable of sliding. This is yet another reason to be wary of steep slopes today.
Predicted SWE totals from 4 am Sunday through 4 am Monday.
Photo: NWS Anchorage