24-25

Shallow soft slabs in Bridgers

The Throne
Bridger Range
Code
SS-AFr-R2-D1-S
Elevation
7500
Aspect
N
Latitude
45.88220
Longitude
-110.95200
Notes

We saw a couple storm slabs that broke in today's snow 4-6" deep, 10-30' wide, and we triggered one 3-4" deep wind slab, "remotely", from a few feet back on a small ridgeline. R2-D1. These slabs were very soft, F- to F hard.

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Foot penetration
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
2
D size
1
Bed Surface
S - Avalanche released within new snow
Problem Type
Wind Slab
Slab Thickness
4.0 inches
Vertical Fall
10ft
Slab Width
30.00ft
Weak Layer Grain type
Precipitation Particles
Images
Shallow soft wind slab, Bridgers 2
Shallow soft wind slab, Bridgers
Snow Observation Source
New snow instabilities in Bridgers
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
24-25

Feb 7 We saw a couple storm slabs that broke in today's snow 4-6" deep, 10-30' wide, and we triggered one 3-4" deep wind slab, "remotely", from a few feet back on a small ridgeline. R2-D1. These slabs were very soft, F- to F hard. Photo: GNFAC

 

Avalanche Details: Shallow soft slabs in Bridgers
Forecast link: GNFAC Avalanche Forecast for Sat Feb 8, 2025GNFAC Avalanche Forecast for Sun Feb 9, 2025
Bridger Range, 2025-02-07
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    • New snow instabilities in Bridgers

    Date
    Activity
    Snowmobiling

    We rode below the Throne and towards Fairy Lake, mostly at elevations 6,800-7,500'. It snowed steady S1-2 most of the day and tapered off in the afternoon. Wind was a stout moderate out of the east and south in the parking lot. Wind was light to moderate out of the south up higher/"mid-mountain". There was a brief clearing mid-day and we could see the bowl and ridge south of Naya Nuki.

    We saw a couple storm slabs that broke in today's snow 4-6" deep, 10-30' wide, and we triggered one 3-4" deep wind slab, "remotely", from a few feet back on a small ridgeline. R2-D1. These slabs were very soft, F- to F hard.

    The interface below this week's storm was generally well bonded to the surface below and lacked a weak layer from the recent high pressure. I would not totally rule out the potential of something breaking wider on a weak layer because we did not get a good look at higher elevations, but so far it seems less likely to have a persistent slab problem involving a layer below this week's snow in the Bridgers as compared to other parts of our forecast area.

    Region
    Bridger Range
    Location (from list)
    The Throne
    Observer Name
    Alex Marienthal

    Wind slab fracture up Taylor’s Fork

    Date
    Activity
    Snowmobiling
    Region
    Southern Madison
    Location (from list)
    Taylor Fork
    Observer Name
    Cheyenne- Ride Rasmussen Style

    Soft Slab Avalanches in Hyalite

    Hyalite - main fork
    Northern Gallatin
    Code
    SS-AFu-R1-D1
    Aspect
    W
    Latitude
    45.44720
    Longitude
    -110.96200
    Notes

    At the base of G2 I triggered a 3 inch x 100 foot soft slab. I was surprised how far it propagated. It looked like it failed on a density change under the morning's new snow. 40 feet up on the first large bench we triggered another slide, 6 inches deep, the entire width of the bench. It could have pushed a climber off if they were in the middle of it. It was snowing steady (1"/hr) and wind was minimal, but a few hours later we could see plumes higher up in the gullies.

    It had such zip to the propagation that I'm thinking it might take a day for it to not be reactive. There was no way we wanted to get on anything open and steep. 

    Number of slides
    2
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Soft slab avalanche
    Trigger
    Foot penetration
    Trigger Modifier
    u-An unintentional release
    R size
    1
    D size
    1
    Problem Type
    Storm Slab
    Slab Thickness
    6.0 inches
    Slab Width
    100.00ft
    Images
    A 3" x 100' soft slab of new snow easily avalanched at the base of G2.
    Snow Observation Source
    Triggering avalanches in Hyalite
    Slab Thickness units
    inches
    Single / Multiple / Red Flag
    Multiple Avalanches
    Advisory Year
    24-25

    Triggering avalanches in Hyalite

    Date
    Activity
    Ice Climbing

    At the base of G2 I triggered a 3 inch x 100 foot soft slab. I was surprised how far it propagated. It looked like it failed on a density change under the morning's new snow. 40 feet up on the first large bench we triggered another slide, 6 inches deep, the entire width of the bench. It could have pushed a climber off if they were in the middle of it. It was snowing steady (1"/hr) and wind was minimal, but a few hours later we could see plumes higher up in the gullies.

    It had such zip to the propagation that I'm thinking it might take a day for it to not be reactive. There was no way we wanted to get on anything open and steep. 

    Region
    Northern Gallatin
    Location (from list)
    Hyalite - main fork
    Observer Name
    Doug Chabot
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