20-21

West facing slope, Hyalite canyon

NORTHERN GALLATIN RANGE
Northern Gallatin
Code
SS-N
Aspect
W
Latitude
45.43380
Longitude
-110.92500
Notes

From obs: "We were ice climbing below Divide Peak today. I heard and saw a natural avalanche across the basin on the west facing slopes below Overlook Mountain, I also observed recent avalanche debris below “The G Spot” which is in a couloir below Overlook. Even though there isn’t any recent snow, the snow that is there is getting actively blown around."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
Problem Type
Wind-Drifted Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
20-21

We triggered this avalanche from 50 feet away. We were walking on a low-angle slope, collapsed the slope, and where the pitch got steeper, we had an avalanche. This is an obvious sign of dangerous instability. If you are on steep slopes it is LIKELY that you will trigger an avalanche. Today, we triggered two avalanches. Photo: GNFAC

Avalanche Details: Two skier triggered slides at Lionhead
Forecast link: GNFAC Avalanche Forecast for Mon Dec 21, 2020GNFAC Avalanche Forecast for Sat Dec 26, 2020
Lionhead Range, 2020-12-20
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    • West facing slope, Hyalite canyon

    Date
    Activity
    Ice Climbing

    We were ice climbing below Divide Peak today. I heard and saw a natural avalanche across the basin on the west facing slopes below Overlook Mountain, I also observed recent avalanche debris below “The G Spot” which is in a couloir below Overlook. Even though there isn’t any recent snow, the snow that is there is getting actively blown around.

    Region
    Northern Gallatin
    Location (from list)
    NORTHERN GALLATIN RANGE
    Observer Name
    Katie McKinstry

    Bradleys

    Date

    Day 2 of AAI Rec 1. Toured up to Bradleys/base of the Ramp today. Was somewhat surprised to find a snowpack generally lacking basal weak layers, in contrast to the Beehive area where we have been operating. Layer of most concern was 10cm FC in mid-pack, above P to K hardness melt forms and rounds (October Snow). Recent snow has drifted into slabs up to 50cm thick. HS is variable, 30-110cm. ECTN on facet layer mid pack.

    Observer Name
    Sam H

    Skier triggered large cornice, Beehive

    Beehive Basin
    Northern Madison
    Code
    C-ASu-R2-D2-O
    Elevation
    8960
    Aspect
    E
    Latitude
    45.32750
    Longitude
    -111.39700
    Notes

    From obs.: "Kicked off a larger than expected cornice as we skinned up the ridge on the W side of Beehive basin. Wind was blowing 20-ish across the opening, cornice had grown pretty good-sized for so little snow. I was making a turn on skins to get back away from the edge when the cornice gave way, probably pulled 25 feet end to end and broke a good 5 feet back from the lee edge of the cornice. I was able to get off the cornice and avoid going over the edge. No activity on the slope below after cornice drop,... although there was a decent hard slab that pulled out just below the ridge when the cornice dropped onto it.... Hard slab on the edges was about 10" deep, some big chunks of cornice on the slope for any future riders..."

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Cornice fall
    Trigger
    Skier
    Trigger Modifier
    u-An unintentional release
    R size
    2
    D size
    2
    Bed Surface
    O - Old snow
    Problem Type
    Wind-Drifted Snow
    Slab Thickness
    10.0 inches
    Slab Width
    25.00ft
    Images
    Skier triggered large cornice in Beehive Basin 3
    Skier triggered large cornice in Beehive Basin 2
    Skier triggered large cornice in Beehive Basin
    Slab Thickness units
    inches
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    20-21
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