20-21

Natural avalanches in Hyalite: A Lowe peak, Flanders

Flanders Creek
Northern Gallatin
Code
HS-N-R2-D2
Elevation
9500
Aspect
N
Latitude
45.44020
Longitude
-110.93100
Notes

From obs: "Skied Mount Blackmore today. Saw a natural avalanche on Alex Lowe peak just south of the Hellmouth,..."

Other group's obs: "I and one friend observed the remains of a natural avalanche below the north facing headwall up Flanders creek. It looked as if it happened within the past few days. I didn’t get close enough to really gauge the size in width but it propagated at the ground. The crown looked to be 3’-4’ deep..."

Number of slides
2
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Problem Type
Persistent Weak Layer
Slab Thickness
36.0 inches
Images
Natural deep slab near Flanders
Natural avalanche near Alex Lowe peak
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
20-21

From obs: "Skied Mount Blackmore today (3/27/21)... around 1 pm a skier remote triggered a deep slab from ~50 feet away (around the corner lookers right in the attached picture). Broke at the ground, 10-15feet deep, and took out a small tree." Photo: M. Lavery

Avalanche Details: Skier remote triggered deep slab near Mt Blackmore
Forecast link: GNFAC Avalanche Forecast for Sun Mar 28, 2021
Northern Gallatin, 2021-03-27
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    • Skier triggered wind slab, S. Madison

    SOUTHERN MADISON RANGE
    Southern Madison
    Code
    SS-AS-R2-D2-S
    Elevation
    10000
    Aspect
    E
    Latitude
    44.97860
    Longitude
    -111.41500
    Notes

    From obs: "We were skinning up Pyramid Point from the East. as we approached 10,000 ft, we encountered a wind slab on an East Facing slope. it was about 1-2 inches where we encountered it but it quickly propogated. the crown was 18-20 inches at its highest and about 150 feet wide. the debris ran for about 200 feet."

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Soft slab avalanche
    Trigger
    Skier
    R size
    2
    D size
    2
    Bed Surface
    S - Avalanche released within new snow
    Problem Type
    Wind-Drifted Snow
    Slab Thickness
    18.0 inches
    Images
    wind slab avalanche, pyramid point
    Slab Thickness units
    inches
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    20-21

    From obs (3/27/21): "We were skinning up Pyramid Point from the East. as we approached 10,000 ft, we encountered a wind slab on an East Facing slope. it was about 1-2 inches where we encountered it, but it quickly propogated. the crown was 18-20 inches at its highest and about 150 feet wide. the debris ran for about 200 feet."

    Avalanche Details: Skier triggered wind slab, S. Madison
    Forecast link: GNFAC Avalanche Forecast for Sun Mar 28, 2021
    Southern Madison, 2021-03-27
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    • Beehive to Bear Basin

    Date
    Activity
    Skiing

    ECTPx at the base of the steep skin to gain the ridge between Bee and Bear. Observed copious blowing snow off the cornices into Bear Basin. We entered Bear Basin from the ridgeline, south of the cornices and dug a pit on low angle terrain below the ridgeline. ECTPx and no shearing or propagation was observed with additional effort.

    Region
    Northern Madison
    Location (from list)
    Beehive Basin
    Observer Name
    Bee-Bear

    Pyramid Point, wind slab avalanche, 10,000ft. East Aspect

    Date
    Activity
    Skiing

    We were skinning up Pyramid Point from the East. as we approached 10,000 ft, we encountered a wind slab on an East Facing slope. it was about 1-2 inches where we encountered it but it quickly propogated. the crown was 18-20 inches at its highest and about 150 feet wide. the debris ran for about 200 feet.

    Region
    Southern Madison
    Location (from list)
    SOUTHERN MADISON RANGE

    Deep Slab Avalanche in Blackmore Basin

    Date
    Activity
    Snowboarding

    My partner and I observed a deep slab avalanche in Blackmore Basin that appeared to break on the depth hoar near the bottom of the snowpack. It was on a wind loaded NE facing slope at approx. 9,500 and looked to break on a slope in the 35-40 degree range. The crown was about 8'-10' deep and 200' wide. It broke to the ground and ripped out several small trees.
    As soon as we saw it, we came over a small ridge to see another skier near the debris. According to him it was triggered remotely by one of the two skiers on the coming down on the lookers right of the slide (in the second photo). We confirmed that a beacon search was done to make sure no one was buried.
    Earlier in the day we dug a pit near the summer on an east facing slope and got no results. After seeing this we avoided avalanche terrain and took a low angle route down. We were glad no one was buried and found some great snow!

    Region
    Northern Gallatin
    Location (from list)
    Mt Blackmore
    Observer Name
    JR Mooney
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