Northern Gallatin

On Thursday, Feb 11, snowmobilers remotely triggered two large avalanche in the Portal Creek area.

From obs: "Broke on lookers right crown first then triggered second slide to lookers left (rocks everywhere). Broke on depth hoar on both slides north facing aspects. Nobody was caught."

Avalanche Details: Remotely triggered avalanches in Portal Creek
Forecast link: GNFAC Avalanche Forecast for Fri Feb 12, 2021
Northern Gallatin, 2021-02-12
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    • Lick Creek, Main Meadow

    Date
    Activity
    Skiing

    8,023ft elevation, SW aspect, 19° incline
    STM ^25cm
    CT13
    ECTP12 (@ same 25cm point)
    1.3° C temperature change per 10cm
    total pit height = 75cm

    Region
    Northern Gallatin
    Location (from list)
    Lick Creek
    Observer Name
    Gage Bodensteiner

    Natural, North Face Alex Lowe

    Alex Lowe Peak
    Northern Gallatin
    Code
    HS-N-R3-D2.5-O
    Aspect
    N
    Latitude
    45.42720
    Longitude
    -111.01400
    Notes

    From Obs: "One large avalanche observed, on the path adjacent to the N Couloir on Alex Lowe. More or less went full path, I would estimate 2m max crown depth. HS-N-R4/D2.5-O. A large cornice fell on the NF of Blackmore with no slab results. Observed several size 1 slabs that failed within new snow during the day on N aspects."

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Hard slab avalanche
    Trigger
    Natural trigger
    R size
    3
    D size
    2.5
    Bed Surface
    O - Old snow
    Problem Type
    Persistent Weak Layer
    Slab Thickness
    200.0 centimeters
    Images
    Alex Lowe N Aspect
    Slab Thickness units
    centimeters
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    20-21

    From Obs 2/9/21: "Up/down the SE Ridge of Blackmore today. No cracking/collapsing observed. One large avalanche observed, on the path adjacent to the N Couloir on Alex Lowe. More or less went full path, I would estimate 2m max crown depth. HS-N-R4/D2.5-O. Observed several size 1 slabs that failed within new snow during the day on N aspects." Photo: S. Hennessey

    Avalanche Details: Natural, North Face Alex Lowe
    Forecast link: GNFAC Avalanche Forecast for Wed Feb 10, 2021GNFAC Avalanche Forecast for Thu Feb 11, 2021
    Northern Gallatin, 2021-02-09
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    • Many natural avalanches on Buck Ridge

    Buck Ridge
    Northern Madison
    Code
    SS-N
    Latitude
    45.17190
    Longitude
    -111.38000
    Notes

    We (GNFAC) observed many (6+) natural avalanches while riding on Buck Ridge. Many looked to be breaking under the storm snow (3+feet; 2.7" SWE), but some looked deeper. We deduced that these ran on Monday, 8 February, because there was only a few inches of snow covering the debris.

    Number caught
    0
    Number buried
    0
    Avalanche Type
    Soft slab avalanche
    Trigger
    Natural trigger
    Problem Type
    New Snow
    Images
    Natural avalanche on Sphinx Mtn.
    Natural avalanche near Slats Hill
    Second Yellowmule natural avalanche
    First Yellowmule natura avalanche
    Attached Videos
    The snowpack needs time to adjust, Buck - 9 Feb
    Slab Thickness units
    centimeters
    Single / Multiple / Red Flag
    Multiple Avalanches
    Advisory Year
    20-21
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