Southern Gallatin

Unreactive tests in the Gallatin

Date
Activity
Skiing

Dug a hasty pit on E facing 23 degree slope at 8100 ft above Sportsman Lake. Overall snow depth 165 cm. Found all the familiar suspects including depth hoar, the Thanksgiving weak layer and two 1F layers between 4F layers in the top 60 cm of the snowpack. CT and ECT both produced no results. Temps were warmer in the valley, but didn't show signs of being above freezing above 7500ft.

We skied mellow terrain anyway and made very sporty turns on our nordic skis.

Region
Southern Gallatin
Location (from list)
SOUTHERN GALLATIN RANGE

Skier unintentionally triggered and was caught in wind slab avalanche on the Y couloir in Sheep Creek Drainage. Skier was carried 10m before self arresting. The slide ran ~250m down and broke across the entire width of the couloir. There were no injuries and skied away. 

Cooke City, 2023-01-09

Looking for instability

Date
Activity
Snowmobiling

We rode into Teepee Basin first. We had perfect visibility and saw no avalanches. We dug on the far north ridge on a south facing slope: HS 105, ECTN25 on facets about 40 cm off the ground. There is a lack of recent ava activity and ECTN score, which point towards a snowpack trending towards stability, but the snowpack structure is still suspect: facets underlying a slab.  

Next we rode to a small and recent avalanche in Cabin Creek. We were alerted to it last night. Although it was steep and wind-loaded, it illustrated the lurking problem we are finding in most areas. Faceted snow is not entirely trusted. We did not see evidence of avalanches on Skyline ridge and folks are starting to climb.

 

Region
Southern Madison
Location (from list)
Cabin Creek
Observer Name
Doug Chabot

We looked at the avalanche that killed a snowmobiler yesterday (12/31/22) on Crown Butte near Cooke City. Our deepest condolences go out to the family and friends of the victim, and those involved with the rescue and recovery. Photo: GNFAC

Cooke City, 2023-01-02

Snowmobiler avalanche fatality on Crown Butte

Crown Butte
Cooke City
Code
HS-AMu-R4-D3-O
Elevation
9800
Aspect
SE
Latitude
45.05250
Longitude
-109.96200
Notes

On December 31, 2022 a snowmobiler was killed in a very large avalanche north of Cooke City, MT. The avalanche occurred near Daisy Pass on Crown Butte on a southeast facing slope at 9,800’. Two brothers (age 17 and 21) from Washington were snowmobiling uphill on adjacent slopes. The older brother was climbing a steeper slope and triggered the avalanche 100-200’ below the top. He was carried 600 vertical feet and buried 5 feet deep. The buried rider was wearing an airbag pack that was not deployed. Both riders had shovels and probes. They were not wearing avalanche beacons. A nearby group of riders rode up to the slide within minutes after it happened, saw a buried snowmobile and began to search for the rider. One rider from that group went into Cooke City to alert Search and Rescue. The buried rider was located with a probe line an hour after the avalanche happened. He was unable to be revived with CPR and AED at the site. The avalanche appeared to be 2-4' deep, 500' wide, 600' vertical, and broke on weak snow near the bottom of the snowpack. AMu-HS-R3/4-D3-O

Our deepest condolences go out to the family, friends, and those involved.  

Full report available here: http://www.mtavalanche.com/accident/22/12/31

 

Number of slides
1
Number caught
1
Number buried
1
Number killed
1
Avalanche Type
Hard slab avalanche
Trigger
Snowmobile
Trigger Modifier
u-An unintentional release
R size
4
D size
3
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
24.0 inches
Vertical Fall
600ft
Slab Width
500.00ft
Weak Layer Grain type
Faceted Crystals
Weak Layer grain size
1.50mm
Weak Layer Hardness
4F
Slab Layer Grain Type
Decomposing and Fragmented precipitation particles
Slab Layer Grain Size
0.30mm
Slab Layer Hardness
P-
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

On December 31, 2022 a snowmobiler was killed in a very large avalanche north of Cooke City, MT. The avalanche occurred near Daisy Pass on Crown Butte on a southeast facing slope at 9,800’. The avalanche appeared to be 2-4' deep, 500' wide, 600' vertical, and broke on weak snow near the bottom of the snowpack. Photo: GNFAC

Cooke City, 2023-01-01