21-22

This is the slope that avalanched and killed a snow bike rider (motorized) on 2/19/22. Photo is from the Search and Rescue team who were leaving the site as it was getting dark, and did not have time to gather more info. Click link below for more details. Photo: B. Zavora


Forecast link: GNFAC Avalanche Forecast for Sun Feb 20, 2022
Cooke City, 2022-02-19
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    • Avalanche Fatality on Miller Mountain (snow bike)

    Sheep Creek
    Cooke City
    Code
    SS-AMu-R3-D3-O
    Elevation
    9800
    Aspect
    S
    Latitude
    45.03900
    Longitude
    -109.98100
    Notes

    On February 19, 2022, three snowmobilers and two snow bikers were in Sheep Creek on the south face of Miller Mountain north of Cooke City. The two snow bikers were high on the slope when one stopped on a small ridge while the other climbed higher and triggered a large avalanche. The avalanche carried him down through a gully and over a cliff where he was partially buried near the toe of the debris. His arm and airbag were visible and his head was 1 foot under the surface. Resuscitation efforts were unsuccessful. The avalanche was 800 feet wide, averaged 2 feet deep (estimated) and ran 1200 vertical feet. The avalanche likely broke on facets and depth hoar at the bottom of the snowpack in an area that was thinly covered and recently wind-loaded. The debris was up to 15 feet deep. The avalanche is classified SS-AMu-R3-D3-O.

    CLICK HERE FOR THE FULL REPORT

    Number of slides
    1
    Number caught
    1
    Number buried
    1
    Number killed
    1
    Avalanche Type
    Soft slab avalanche
    Trigger
    Snowmobile
    Trigger Modifier
    u-An unintentional release
    R size
    3
    D size
    3
    Bed Surface
    O - Old snow
    Problem Type
    Persistent Weak Layer
    Slab Thickness
    24.0 inches
    Vertical Fall
    1200ft
    Slab Width
    800.00ft
    Images
    Sheep Creek avalanche, GE locations
    Sheep Creek avalanche, GE far
    Attached Videos
    Snow biker avalanche fatality, Cooke City - 21 Feb
    Slab Thickness units
    inches
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    21-22

    Skier triggered wind slab on Town Hill

    Town Hill
    Cooke City
    Code
    SS-ASc-R2-D1.5-I
    Elevation
    8500
    Aspect
    SE
    Latitude
    45.02560
    Longitude
    -109.93700
    Notes

    From IG message: "I initiated a ski cut below a cornice and roller, and was able to trigger a wind slab that broke roughly 15 inches deep and 30-50 feet across and slid a few hundred feet down slope. Same problem from last night, but more volume and energy today."

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Soft slab avalanche
    Trigger
    Skier
    Trigger Modifier
    c-A controlled or intentional release by the indicated trigger
    R size
    2
    D size
    1.5
    Bed Surface
    I - Interface between new and old snow
    Problem Type
    Wind-Drifted Snow
    Slab Thickness
    15.0 inches
    Vertical Fall
    200ft
    Slab Width
    40.00ft
    Images
    Skier triggered wind slab on Town Hill, 2/19 (2)
    Skier triggered wind slab on Town Hill, 2/19
    Slab Thickness units
    inches
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    21-22
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