21-22

From obs 2/27/22: "Skied Flanders mountain today. Dug a snowpit on a SE facing 24 deg slope at 9700 feet. ECTN24 30cm down on a layer of facets just under an ice crust. Snow above the ice crust was 4F- at most and not hard enough for anything to propagate. Winds were moderate and gusty, transporting a decent amount of snow but not really forming any slabs other than at the ridgeline. I triggered a shallow 2-3cm deep windslab about 20 feet wide just below the ridgeline. I was not on a steep slope, so it barely moved.... didn't see any other signs of instability." Photo: M. Lavery

Northern Gallatin, 2022-02-28

Collapse and "whumph" on Scotch Bonnet

Scotch Bonnet
Cooke City
Code
SS-AS-O
Elevation
10150
Aspect
SW
Latitude
45.07330
Longitude
-109.94800
Notes

On 2/27/22 while touring near the top of Rasta Chutes on Scotch Bonnet Mtn. near Cooke City we triggered a collapse of the snowpack and heard a loud "whumph". A 8-10" slab failed and propagated on a layer of weak, sugary facets on top of a hard melt-freeze crust. Estimated 40 feet wide.

Number of slides
0
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Red Flag
Advisory Year

Small skier and rider triggered slides near Cooke

Lulu Pass
Cooke City
Code
SS-AS-R1-D1
Elevation
10000
Aspect
E
Latitude
45.07090
Longitude
-109.95800
Notes

Photo is of a slide that was triggered by a skier on 2/26/22 on Rob's Knob near Lulu Pass. We saw 3 other similar sized slides on 2/27/22 while riding between Lulu Pass and Goose Creek.

Number of slides
4
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
R size
1
D size
1
Problem Type
Persistent Weak Layer
Slab Thickness
10.0 inches
Vertical Fall
250ft
Slab Width
30.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Shooting Cracks in Specimen Creek

Date
Activity
Skiing

Shooting cracks in a thin wind slab on a ridge crest. The slab was small but the collapse was abrupt and propagated 20 feet.

Region
Southern Gallatin
Location (from list)
Specimen Creek
Observer Name
Jack Taylor

Snowmobile triggered slide near Goose Creek, Cooke

Goose Creek
Cooke City
Code
SS-AMu-R3-D1.5-O
Elevation
9000
Aspect
SE
Latitude
45.09230
Longitude
-109.95100
Notes

This slide was triggered by a sledder on 2/26/22 around 1pm near Goose Creek outside Cooke City.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
u-An unintentional release
R size
3
D size
1.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
18.0 inches
Vertical Fall
50ft
Slab Width
75.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Snowmobile triggered hard slab, Sheep Mtn., Cooke

Sheep Mountain
Cooke City
Code
HS-AM-R2-D1.5-O
Elevation
10000
Aspect
NW
Latitude
45.07220
Longitude
-109.92800
Notes

We saw this avalanche the afternoon of 2/27/22, on a north facing slope on Sheep Mtn. near Cooke City. It appeared less than 24 hours old and likely snowmobile triggered.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Snowmobile
R size
2
D size
1.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
30.0 inches
Vertical Fall
30ft
Slab Width
100.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

We saw this avalanche the afternoon of 2/27/22, on a north facing slope on Sheep Mtn. near Cooke City. It appeared less than 24 hours old and likely snowmobile triggered. Photo: GNFAC

Cooke City, 2022-02-27