Avalanche
- Slab Width
- 152 m
- Weak Layer
- Facets
- Trigger Type
- Natural
- Vertical Fall
- 183 m
- Avalanche Type
- Hard Slab
- Slab Thickness
- 46 cm
- Start Zone Aspect
- Northeast
- Avalanche Problem
- Persistent Weak Layer
- Start Zone Elevation
- 3505 m
This avalanche ran during the Feb 20 storm event that put down 14" of new snow capping off a week long storm event that totaled 18" at 1.2" SWE. Strong SW winds early in the cycle built pencil hard slabs 2'-3' thick on N and E aspects at treeline and above. These were resting on the previous week's 5" that preserved the Feb 11 faceted layer. Hang fire prevented closer inspection but depth indicated that this avalanche failed on the Feb 11 faceted layer. Much of the slide wasn't visible from the ridge but it appeared to have propagated much wider beneath a convexity. It also likely stepped down into deeper layers below there as has been the trend. This avalanche occurred a few hundred yards further up the ridge than the one we intentionally triggered on Feb 19.
This photo was taken from the West Shoulder of Mellenthin on 2/24. A great look at this avalanche. A "step-down" to the ground is visible just above the steep convexity.