22-23

From email 2/24/23: "Triggered a small 2’ deep wind slab in new snow this afternoon.  NNE aspect 9,500’, approximately 38° slope.  Riding was excellent on all high North facing slopes and this was the only sign of instability we saw all day.  Wind was howling on the way out, lots of snow coming out of the trees and transporting at ridge tops."

Northern Madison, 2023-02-25

Large avalanche in Sheep Creek from 2/21: "slide in the photo looked to be an average of about 2-4' deep (6' deep in places) and about 800-1000' wide, spanning across lots of different terrain features.

I also noticed that the main south facing slide path off of Miller Mountain avalanched very large as well. (the same avalanche path where the snowbiker was killed last winter)  I couldn't see the crown, but the debris ran to the valley bottom and appears to have flattened a large stand of mature timber." Photo: B. Fredlund

 

Cooke City, 2023-02-25

Natural wind slab in Lamar

Yellowstone Park NE
Cooke City
Code
HS-N-R2-D1-I
Elevation
6900
Aspect
SE
Latitude
45.00340
Longitude
-110.04300
Notes

As seen from the highway, Lamar Valley, SE aspect. Mid-morning today. -3°. 

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
2
D size
1
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
10.0 inches
Vertical Fall
50ft
Slab Width
30.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Natural avalanche on Emigrant Peak

Date
Activity
Skiing

From IG message 2/24/23: HS-N-R2.5-D2-O. In emigrant gulch on an east aspect around 9k feet. Seemed to have stepped down on to a PWL, however it’s pretty tough to tell.

 

 

Region
Out of Advisory Area
Location (from list)
Emigrant Peak
Observer Name
Owen Desroches

Large natural wind slab avalanche Mt. Blackmore

Date
Activity
Skiing

From IG: Skiers near Mt. Blackmore on 2/24 saw a large avalanche on the east side of Mt. Blackmore that appeared to have happened in the last 24 hours.

Region
Northern Gallatin
Location (from list)
Mt Blackmore

Rider triggered wind slab Buck Ridge

Date
Activity
Snowmobiling

Triggered a small 2’ deep wind slab in new snow this afternoon.  NNE aspect 9,500’, approximately 38° slope.  Riding was excellent on all high North facing slopes and this was the only sign of instability we saw all day.  Wind was howling on the way out, lots of snow coming out of the trees and transporting at ridge tops.

Region
Northern Madison
Location (from list)
Buck Ridge

Avalanche photos from Sheep Creek

Date
Activity
Skiing

There were large slab avalanches that happened on both sides of the valley.  Northerly and southerly aspects.  

I was particularly impressed by the width of one of the slides Nate observed yesterday.  (one of the 2 photos attached).  That slide in the photo looked to be an average of about 2-4' deep (6' deep in places) and about 800-1000' wide, spanning across lots of different terrain features.

I also noticed that the main south facing slide path off of Miller Mountain avalanched very large as well. (the same avalanche path where the snowbiker was killed last winter)  I couldn't see the crown, but the debris ran to the valley bottom and appears to have flattened a large stand of mature timber.

VERY windy out there today.  Primarily SWerly, but blowing in all directions and moving LOTS of snow.  Natural avalanches likely happening today.

 

Region
Cooke City
Location (from list)
Sheep Creek
Observer Name
Beau Fredlund

Wind slab in Lamar

Date
Activity
Skiing

As seen from the highway, Lamar Valley, SE aspect. Mid-morning today. -3°. 

Region
Cooke City
Location (from list)
Yellowstone Park NE
Observer Name
T. Parrie