Cornice triggered avalanche in Hourglass, Bridgers

Hourglass Chute
Bridger Range
Code
HS-NC-R3-D2.5-O
Elevation
8300
Aspect
E
Latitude
45.83300
Longitude
-110.93800
Notes

HS-R3-D3

3-4’ crown skiers left usual wind loaded side appeared to be started by a natural cornice drop.
 
There was a 4-5’ crown lower below the pinch on the skiers right wall. The toe of the debris stopped just short of the low meadow. It appeared that it ran on the November rain crust
 
3 people who did not witness anything but skied up on the crown at 3:40ish performed a transceiver search with no results. It appeared that the avalanche was a few hours old. 
 
Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Cornice fall
R size
3
D size
2.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
48.0 inches
Vertical Fall
800ft
Slab Width
100.00ft
Weak Layer Grain type
Depth Hoar
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year