Wind Slabs
- Alpine
- Treeline
- Below treeline
- Likelihood
- Likely
- Size
- 1–2
Five inches of new snow fell overnight in the upper elevations of the Snake River Range. Another 4-6 inches of snow accompanied by moderate winds out of the southwest/west is expected to fall throughout the day. Newly formed soft slabs up to 18 inches deep will be sensitive to the weight of a rider in very steep (>35°) and wind loaded terrain above 8,000’. Wind slabs will be smaller and isolated to very steep terrain at the low elevations. Be on the lookout for signs of instability including cracking within the new snow or recent avalanches. Move to low angle terrain if these signs are present.
Although less likely, larger avalanches up to 3 feet deep could be triggered on some very steep and wind affected slopes above 8,500’. Weak interfaces below older wind slabs have resulted in several large human triggered avalanches the last several days. New snow and wind loading is stressing these deeper layers and could make them more sensitive to triggering today.Carefully assess the snowpack in wind affected and very steep terrain to determine if the potential for deeper avalanches exist. Giving very steep and wind loaded features a wide margin is the best way to manage this problem today.
(3/21/2025)
This avalanche was remotely triggered by a snowmobile yesterday in Mosquito Creek and is a good example of terrain where deeper avalanches involving older wind slabs are possible. NE aspect at 9,100'. The avalanche failed on old snow around 2-3 feet deep.