Avalanche: Gravel Pit Lanes

Observer Name
Trenbeath
Observation Date
Tuesday, December 29, 2020
Avalanche Date
Monday, December 28, 2020
Region
Moab » Gold Basin » Tukno NE Face » Gravel Pit Lanes
Location Name or Route
Gravel Pit Lanes
Elevation
11,400'
Aspect
Northeast
Slope Angle
Unknown
Trigger
Natural
Avalanche Type
Soft Slab
Avalanche Problem
Persistent Weak Layer
Weak Layer
Facets
Depth
2'
Width
150'
Vertical
900'
Comments
Dave Garcia photos
First natural cycle of the season. After an extended dry spell, 12"-20" of snow accompanied by mod-strong SW winds placed a significant load on a shallow and fragile snowpack. Did not get close enough to observe the crown but snowpits dug that day, and up to this point throughout the season, revealed a stratified and faceted snowpack, with the primary layer of concern being a weak layer of loose facets from early November storms sitting on top of a faceted, knife hard, melt-freeze layer formed in late October. We also observed a weak layer higher up in the snowpack that failed with a score of ECTP18, and this could also be the culprit, but due to widespread sensitivity and collapsing on the deeper, faceted layer above the crust at 35 cm, I'm inclined to believe that is the weak layer involved here. As the avalanche moved down the slope it released the gully walls as a separate slab further down. It also likely caused a sympathetic release of the avalanche visible at the lower, mid-left of the photo.
Video
Coordinates