Photo: H Meyers
24-25
Saw a small recent looking storm slab avalanche that appeared to be naturally triggered above the road on a south facing slope around 6000'. It ran all the way across the slope ~30' wide and ~4" deep within the recent snow. The snow didn't move far enough to reach the road. The slope was quite steep-- we didn't measure but I'd estimate 40*.
Photo: H Meyers
Avalanche Details: Small Storm Snow Avalanches in Brackett Creek
Forecast link: GNFAC Avalanche Forecast for Sun Jan 5, 2025
Bridger Range, 2025-01-04
Forecast link: GNFAC Avalanche Forecast for Sun Jan 5, 2025
Touchy Storm Slabs in N. Gallatin
Date
Activity
Skiing
We toured into some mid-elevation skiing in the N Gallatin on Wheeler Mountain. I was surprised that we weren't getting collapsing, given the recent loading, but, at the end of the day, I only heard one localized collapse.
The big message from the day was touchy surface conditions. When the storm abated in the afternoon, there was 9" of new snow. The most recent pulse of snow came in upside down, and we observed cracking in the top 9" every time we moved into slightly steeper terrain. We saw one R1-D1 natural avalanche on a ~35 degree slope (this was the steepest terrain we visualized today). The slide broke 15-20' wide and ran less than 50 feet. This storm slab instability will heal relatively quickly, but I expect to trigger D1 and 2 avalanches on most steep terrain today and maybe tomorrow.
We tested the deeper weak layer with an ECT at the top of the meadows (ECTP25). Again, I was surprised by the lack of evidence of deeper instability. I wouldn't trust it until we get a few more data points and we get some visibility to assess avalanche activity.
Region
Northern Gallatin
Location (from list)
Wheeler Mountain
Observer Name
Dave Zinn
Natural storm slab at Brackett Creek
Date
Activity
Skiing
Saw a small recent looking storm slab avalanche that appeared to be naturally triggered above the road on a south facing slope around 6000'. It ran all the way across the slope ~30' wide and ~4" deep within the recent snow. The snow didn't move far enough to reach the road. The slope was quite steep-- we didn't measure but I'd estimate 40*.
We also had localized cracking around our skis with planar breaks on that interface throughout the day, as well as a shooting crack when a member of our group jumped on a south facing test slope. On our way back down we saw an even smaller (~10' across) avalanche on a SW facing creek bank that appeared to be triggered by another party as a test slope. Both of these test slopes were steep and we had no results on two other, less steep slopes.
Region
Bridger Range
Location (from list)
Brackett Creek
Observer Name
Heather Myers
Remote Triggered Avalanche in Lionhead
LIONHEAD AREA
Lionhead Range
Code
SS-AMr-R2-D2.5-O
Elevation
9340
Aspect
SE
Latitude
44.72690
Longitude
-111.31800
Notes
Remote triggered this avalanche at Lionhead. We were snowmobiling to the left of where the avalanche occurred. No one was caught.
Coordinates: 44°43'36.8"N 111°19'05.0"W
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
2
D size
2.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
24.0 inches
Vertical Fall
400ft
Slab Width
300.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
Remote triggered this avalanche at Lionhead. We were snowmobiling to the left of where the avalanche occurred. No one was caught.
Coordinates: 44°43'36.8"N 111°19'05.0"W
Photo: Ben
Avalanche Details: Remote Triggered Avalanche in Lionhead
Lionhead Range, 2025-01-04
Small Storm Snow Avalanches in Brackett Creek
Ross Peak
Bridger Range
Code
SS-N-R1-D1
Elevation
6000
Aspect
S
Latitude
45.86010
Longitude
-110.94900
Notes
From obs: "Toured up to the low angle meadows on the NE shoulder of Ross Peak. Dug a 8000ft and found no action in an extended column test but a significant result in a propagation saw test (PST END 20/100) at about 90 cm down. Some recent small avalanches in steep terrain along Brackett Creek that broke naturally within the storm snow from 1/3."
From obs: "Saw a small recent looking storm slab avalanche that appeared to be naturally triggered above the road on a south facing slope around 6000'. It ran all the way across the slope ~30' wide and ~4" deep within the recent snow. The snow didn't move far enough to reach the road. The slope was quite steep-- we didn't measure but I'd estimate 40*.
We also had localized cracking around our skis with planar breaks on that interface throughout the day, as well as a shooting crack when a member of our group jumped on a south facing test slope. On our way back down we saw an even smaller (~10' across) avalanche on a SW facing creek bank that appeared to be triggered by another party as a test slope. Both of these test slopes were steep and we had no results on two other, less steep slopes."
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
1
D size
1
Problem Type
New Snow
Slab Thickness
4.0 inches
Slab Width
30.00ft
Images
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year