Skier triggered on Emigrant Peak

Emigrant Peak
Out of Advisory Area
Code
HS-ASu-R3-D3-O
Elevation
9800
Aspect
N
Latitude
45.26290
Longitude
-110.70700
Notes
From an email:
 
This was triggered Christmas Eve day while skinning up a ridge in the mountains east of Emigrant Peak. It broke about 8' back from the cornice/drift right near my ski tips. I instinctively did a quick drop and roll away even though it was unnecessary. Pretty pulse quickening. I didn't get great pictures as I was heading up the ridge and the light was bad. You can pick out the debris flow by its lighter shade of white and see chunks of cornice/slab that got hung up in the starting zone.
 
North Facing aspect at approx. 9800' on a west to east ridge.Slope angles are 35-40. Crown varied from 1-3'. Hard slab on the the cornice propagated to two other small starting zones and pulled the cornices and all the faceted snow near the ridgeline. Avalanche ran about 800'. 
 
The last few week's weather has really weakened what was starting off to be a decent base.  Now the winds have capped a a lot of zones with a hard slab pockets.
 
Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
3
D size
3
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
100.0 centimeters
Vertical Fall
800ft
Slab Width
100.00ft
Slab Thickness units
centimeters