Double Avalanche Fatality, Scotch Bonnet Mountain

Scotch Bonnet
Cooke City
Code
SS-AMu-R2-D2.5-O
Elevation
10000
Aspect
SE
Latitude
45.05660
Longitude
-109.95100
Notes

On December 27, two snowmobilers were caught and killed in an avalanche on Scotch Bonnet Mountain, north of Cooke City. A group of 8 snowmobilers from Minnesota were on their second day of riding when 2 of their machines got stuck on the SE face of Scotch Bonnet Mountain. Two members of their group rode up to help them dig out and the avalanche was triggered soon after. It broke 4-5 feet deep, ran 300 feet wide and 500 feet vertical and killed 2 riders, burying them under 4-5 feet of debris. Everyone had rescue equipment and they were recovered by their party. Park County Sheriff Search and Rescue brought the victims to town. The avalanche broke on a layer of facets 1.5 feet off the ground underneath a thick slab of wind drifted snow. The avalanche is classified SS-AMu-R2-D2.5-O.

 

Number of slides
1
Number caught
2
Number buried
2
Number killed
2
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
u-An unintentional release
R size
2
D size
2.5
Bed Surface
O - Old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
60.0 inches
Vertical Fall
500ft
Slab Width
300.00ft
Weak Layer Grain type
Faceted Crystals
Weak Layer grain size
4.00mm
Weak Layer Hardness
4F-
Slab Layer Grain Type
Wind Broken precipitation particles
Slab Layer Grain Size
0.50mm
Slab Layer Hardness
1F+
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year