Avalanche: Alexander Basin

Observer Name
Grainger
Observation Date
Tuesday, December 17, 2019
Avalanche Date
Monday, December 16, 2019
Region
Salt Lake » Mill Creek Canyon » Alexander Basin
Location Name or Route
Alexander Basin
Elevation
9,900'
Aspect
Northeast
Slope Angle
40°
Trigger
Unknown
Trigger: additional info
Repeater
Avalanche Type
Soft Slab
Avalanche Problem
Persistent Weak Layer
Weak Layer
Facets
Depth
2.5'
Width
350'
Vertical
800'
Snow Profile Comments
Along with the avalanche that Tyler v noted on 12/16 I found 2 other slides east off the Northern Gobbler's ridgeline that likely occurred on the tail end of last weekend's W wind. The cornices along Depth Hoar and East Bowls are well-developed and the 3 slides were all repeaters from Thanksgiving, thinking triggered by cornice fall (unknown if cornices fell naturally or the lower 2 were human-triggered). In 3 ECTs on N-facing with an HS 125cm and problematic Oct. facets 90 cm down, had 2 ECTXs and 1 ECTP30 on that layer (under the deteriorating Nov. crust.
Comments
This slide in Alexander's East Bowl I roughly estimated 350' wide and running to the flats below (in red) ~800' vert. Primarily ran on top of the November crust that was re-faceted after its first run but in places it stepped down to Oct. facets ~3' deep. Looks to be cornice-triggered whether natural or human, did not see tracks close enough to ridge to trigger but not ruling it out.
Debris hard to tell measurements but based on volume and vertical relief would not be surprised at D3.
Comments
This slide was next sub-drainage up from Tyler v's documented in Depth Hoar Bowl, around 45' wide, also running on top of the faceted November crust as a repeater.
Coordinates