18-19

Explosive triggered avalanche at Y.C. on persistent weak layer

Yellowstone Club
Northern Madison
Code
SS-ABc-R3-D2-G
Elevation
8400
Aspect
NE
Latitude
45.24250
Longitude
-111.42900
Notes

Ski patrol triggered this avalanche at the Yellowsone Club on Sunday (12/16). "8400’, ENE facing, 36deg start zone that was about 120’ wide and ran vertically 200’. The crown was 1.5-2’, went to ground, and was a mostly faceted snowpack with a bit of wind effected snow in the top few inches. The slide was released from a 4lb air blast." -YCSP

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
An explosive detonated above the snow surface (air blast)
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
3
D size
2
Bed Surface
G - Ground
Problem Type
Persistent Weak Layer
Slab Thickness
24.0 inches
Vertical Fall
200ft
Slab Width
120.00ft
Weak Layer Grain type
Faceted Crystals
Slab Layer Grain Type
Wind packed
Images
Explosive triggered avalanche at Y.C., debris
Explosive triggered avalanche at Y.C., crown
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
18-19

Ski patrol triggered this avalanche at the Yellowstone Club on Sunday (12/16). "R3/D2 (8400’, ENE facing, 36deg start zone) that was about 120’ wide and ran vertically 200’. The crown was 1.5-2’, went to ground, and was a mostly faceted snowpack with a bit of wind effected snow in the top few inches. The slide was released from a 4lb air blast." Photo: YCSP

Avalanche Details: Explosive triggered avalanche at Y.C. on persistent weak layer
Forecast link: GNFAC Avalanche Forecast for Mon Dec 17, 2018
Northern Madison, 2018-12-17
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    • Ski patrol triggered this avalanche at the Yellowstone Club on Sunday (12/16). "R3/D2 (8400’, ENE facing, 36deg start zone) that was about 120’ wide and ran vertically 200’. The crown was 1.5-2’, went to ground, and was a mostly faceted snowpack with a bit of wind effected snow in the top few inches. The slide was released from a 4lb air blast." Photo: YCSP

    Avalanche Details: Explosive triggered avalanche at Y.C. on persistent weak layer
    Forecast link: GNFAC Avalanche Forecast for Thu Dec 20, 2018
    Northern Madison, 2018-12-17
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    • Snowmobile triggered avalanche on Buck Ridge

    Buck Ridge
    Northern Madison
    Code
    HS-AMu-R3-D2-O
    Elevation
    9100
    Latitude
    45.16330
    Longitude
    -111.31000
    Notes

    A snowmobiler triggered this slide yesterday while sidehilling on the leeward side of a ridge. Estimated crown was about 50' wide and broke about 12-18” deep.

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Hard slab avalanche
    Trigger
    Snowmobile
    Trigger Modifier
    u-An unintentional release
    R size
    3
    D size
    2
    Bed Surface
    O - Old snow
    Problem Type
    Persistent Weak Layer
    Slab Thickness
    16.0 inches
    Vertical Fall
    50ft
    Slab Width
    75.00ft
    Images
    Snowmobile triggered avalanche on Buck Ridge
    Slab Thickness units
    inches
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    18-19

    A snowmobiler triggered this avalanche on Saturday (12/15) near Buck Ridge. It is on a wind loaded slope and likely broke on buried facets that formed in early December.

    Avalanche Details: Snowmobile triggered avalanche on Buck Ridge
    Forecast link: GNFAC Avalanche Forecast for Mon Dec 17, 2018GNFAC Avalanche Forecast for Thu Dec 20, 2018GNFAC Avalanche Forecast for Sat Dec 22, 2018
    Northern Madison, 2018-12-16
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    • This wind-loaded slope was triggered Sunday morning (12/16) by a snowmobiler. The debris was hard slabs of wind-drifted snow. The avalanche broke on a layer of small sized facets that formed during the frigid, clear weather 10 days ago. No one was caught. Photo: GNFAC

    Avalanche Details: Snowmobiler triggered wind slab on Buck Ridge
    Forecast link: GNFAC Avalanche Forecast for Wed Dec 19, 2018GNFAC Avalanche Forecast for Fri Dec 21, 2018
    Northern Madison, 2018-12-16
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    • Snowmobiler triggered wind slab on Buck Ridge

    Buck Ridge
    Northern Madison
    Code
    HS-AMu-R2-D2-O
    Elevation
    9400
    Aspect
    N
    Latitude
    45.18210
    Longitude
    -111.41300
    Notes

    This avalanche was around the corner from the snowpit we dug in 2nd Yellowmule. It looked as though it was triggered about the same time we were digging. The slide failed on near-surface facets that formed 10 days ago that are underneath a hard slab of wind-drifted snow.

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Hard slab avalanche
    Trigger
    Snowmobile
    Trigger Modifier
    u-An unintentional release
    R size
    2
    D size
    2
    Bed Surface
    O - Old snow
    Problem Type
    Wind-Drifted Snow
    Slab Thickness
    50.0 centimeters
    Vertical Fall
    100ft
    Slab Width
    150.00ft
    Weak Layer Grain type
    Near surface faceted particles
    Weak Layer Hardness
    F
    Slab Layer Grain Type
    Wind Broken precipitation particles
    Images
    Snowmobile triggered avalanche, 2nd Yellowmule
    Second yellow mule profile - 16 Dec
    Snomo triggered avalanche in 2nd Yellowmule
    Instability on Buck Ridge
    Attached Videos
    Action in 2nd Yellowmule
    Slab Thickness units
    centimeters
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    18-19
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