Avalanche
- Slab Width
- 61 m
- Weak Layer
- New Snow/Old Snow Interface
- Vertical Fall
- 213 m
- Avalanche Type
- Soft Slab
- Slab Thickness
- 61 cm
- Start Zone Aspect
- Northwest
- Avalanche Problem
- Persistent Weak Layer
- Start Zone Elevation
- 3261 m
Middle one of the birthday chutes. Entire chute went. Multiple crowns, slid to the ground level layer. Debris run all the way down to the flats. Saw a track close to the crown but it traversed back to the ridge.
Forecaster Comments: This avalanche was originally reported on 11/25/2023. The UAC forecaster team went in to look at it on November 29, 2023. Our impression was that this was a D2 (large enough to bury a person) avalanche that ran on dry facets above a crust approximately 1' off the ground. Total depth of snow adjacent to this avalanche at 10,340' was 42" (107cm) and the test results showed ECTX x 2. However, a propagation saw test PST in the dry facets above the dirt crust showed propagation to the end. There were a couple of different avalanche crown faces in this slide. There was an initial crown down off the ridge in the center of the chute, another propagating crown under the cliff band half way down, and the lower riders left flank (where it had been wind loaded) pulled out to the ground.
It was really hard to tell what the trigger may have been. We did observe at least one track in on the riders left flank. We couldn't see a track out and were unsure of the timing of the track so we did a quick beacon search on the debris pile, finding no signals. There were multiple tracks on the lower angle slopes to the west of this avalanche and we observed some signs of settlement and cracking in nearby lower angle slopes from previous days.