East Slopes Central - Lake Chelan to South of I-90
Feb. 3, 2018, noon PST
Weather: Windy and warm. Light mixed rain/snow at times.
Snowpack: We found highly variable snowpack depths in the zone, due to previous wind redistribution. Overall a shallow, but fairly strong snowpack with the exception of a persistent weak layer. We dug a profile and were able to get consistent results that indicated propagation was likely if failure occurred on a persistent weak layer above a translucent rain crust. This layer was buried surface hoar up to 9mm in size. We found this in a number of pits on a test slope near 6000ft. on an ENE aspect. The depth of this layer varied between 40cm and 80cm down from the surface. The only visual clues to instability we found without digging were some minor rollers indicating Loose Wet potential. No observations of recent avalanches on this layer, no whumphing/collapsing, and no shooting cracks tells us that this persistent weak layer is unlikely to be triggered at the moment, though consequences could be high if it were.
Area Description: Below Mission Peak just North of the ski area boundary.
Observation by Primomo Northwest Mtn School AIARE 2
Did you see any avalanches? No
Did you trigger any avalanches? No
Was anyone caught in an Avalanche? No