Snowmobile triggered avalanche in Teepee Basin.
24-25
Snowmobile Triggered Avalanche and Partial Burial in Teepee Basin
Tepee Basin
Southern Madison
Code
SS-AMu-R2-D2
Aspect
NE
Latitude
44.90410
Longitude
-111.18500
Notes
Snowmobile triggered wind slab avalanche in Teepee Basin. One rider was caught, carried and partially buried. Visible arm and leg above snow allowed for successful partner rescue within 20 seconds of burial.
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
u-An unintentional release
R size
2
D size
2
Problem Type
Wind-Drifted Snow
Slab Thickness
36.0 inches
Slab Width
255.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
PWL and Wind Slab Avalanches in the S Madisons
Taylor Fork
Southern Madison
Code
SS-N-R2-D2
Latitude
45.06070
Longitude
-111.27200
Notes
We saw up to five recent avalanches from the last few days. 1-2 looked to have failed on PWLs, and the rest were wind slabs. Cornice collapses triggered at least two of these avalanches.
1. Cornice triggered wind slab in Sunlight Basin
2. Cornice triggered avalanche in Sage Creek
3. Likely PWL avalanche W of Kirkwood Ridge, lower in Cabin Creek
4. Older wind slab SW flank, Sage Peak
5. Likely PWL avalanche backside of Sage Peak
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Problem Type
Wind-Drifted Snow
Attached Videos
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
Whumpfs and Shooting Cracks in Sunlight Basin
Taylor Fork
Southern Madison
Code
Latitude
45.06070
Longitude
-111.27200
Notes
While traversing to our pit site in Sunlight Basin, we triggered a whumpfing collapse and a shooting crack up to 100' long across an adjacent slope. This snowpit on a SE aspect was made up of a dense slab of recent snow, sitting on top of many different layers of junky, faceted grains. Propagation was easy to find (ECTP 11, HS: 112).
Number caught
0
Number buried
0
Images
Attached Videos
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Red Flag
Advisory Year
Large cornice fall triggered avalanche in Sage Creek, Photo: GNFAC
Avalanche Details: PWL and Wind Slab Avalanches in the S Madisons
Southern Madison, 2025-02-21
This snowpit on a SE aspect was made up of a dense slab of recent snow, sitting on top of many different layers of junky, faceted grains. Propagation was easy to find (ECTP 11, HS: 112). Photo: GNFAC
Avalanche Details: Whumpfs and Shooting Cracks in Sunlight Basin
Southern Madison, 2025-02-21
We saw up to five recent avalanches from the last few days. 1-2 looked to have failed on PWLs, and the rest were wind slabs. Cornice collapses triggered at least two of these avalanches. Photo: GNFAC
Avalanche Details: PWL and Wind Slab Avalanches in the S Madisons
Southern Madison, 2025-02-21
Unstable weak layers in the S Madisons
Date
Activity
Snowmobiling
Clear skies, sunshine and great visibility today allowed us to cover a lot of ground in the Southern Madisons. We traveled up the Taylor Fork to the weather station in Sunlight Basin, over to the head of Carrot Basin, through Sage Basin and up and over into Cub and Cabin Creeks.
Winds were light all day and only picked up later in the afternoon, gusting moderately from the south in the parking lot. Solar aspects moistened in the upper 1-2" of the snowpack, but we noted minimal signs of wet snow instability.
We came to the Taylor Fork searching for signs of instability from persistent weak layers and wind slabs, and we found both. We saw up to five recent avalanches from the last few days. 1-2 looked to have failed on PWLs, and the rest were wind slabs. Cornice collapses triggered at least two of these avalanches.
Outside of recent avalanches, a few other red flags jumped out at us. While traversing to our pit site in Sunlight Basin, we triggered a whumpfing collapse and a shooting crack up to 100' long across an adjacent slope. This snowpit on a SE aspect was made up of a dense slab of recent snow, sitting on top of many different layers of junky, faceted grains. Propagation was easy to find (ECTP 11, HS: 112). We also dug snowpits on N and SW facing slopes. While we found weak snow on these slopes, the N (ECTPX) and SW (ECTP25), the snowpack was deeper in both areas and the weak layers were less developed. When compared to what Alex and Mark found three weeks ago in this area, these instabilities are becoming less widespread and more stubborn to trigger, but an avalanche breaking on these weak layers is still possible.
Region
Southern Madison
Location (from list)
Taylor Fork
Observer Name
Haylee Darby