Large Skier Triggered Avalanche Hyalite Pk

Hyalite Peak
Northern Gallatin
Code
HS-ASu-R4-D3-O
Elevation
9800
Aspect
NE
Latitude
45.38100
Longitude
-110.96100
Notes

(NE, HS, ASu, D3, R4)

We toured into Hyalite with the intention of skiing the North East Face of Hyalite Peak. Our primary concern was wind loading on leeward slopes. Before starting the day 6" of snow was reported in the Northern Gallatin range however we only found up to three inches of new snow. Approaching the saddle we found soft snow (2-3") on a pencil-hard crust. Once reaching the summit we descended carefully onto the NE face observing a shooting crack on a pocketed soft wind-slab after performing a ski cut. Noting this we descended further staying on the ridgeline. We then found a similar snowpack to the saddle with no cracking after a few more ski cuts and decided to ski one at a time down the duration of the face. Skier 1 skied a few turns down the face when a loud wumph was heard and the whole face started sliding. Skier 1 was caught, carried, and partially buried at the tail of the slide path. Skier 2 observed skier 1 and skied down to them after the avalanche stopped. Skier 1 was then fully dug out and both skiers left the avalanche path unharmed. The slide was thought to be (D3,R4) breaking all the way to the ground and spanning at least 500' wide.

Number of slides
1
Number caught
1
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
4
D size
3
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
54.0 inches
Vertical Fall
700ft
Slab Width
750.00ft
Weak Layer Grain type
Faceted Crystals
Weak Layer grain size
2.50mm
Weak Layer Hardness
F
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year