20-21

Dudley Creek, N - NE Aspect

Date
Activity
Skiing

Went for an evening tour up Dudley Creek to check out the N/NE facing meadows. Wind loading formed a dense slab, but in this particular area, the slab was isolated to the ridgeline and was not present even just below the ridge (pit location). Both a CT and ECT failed at the same interface about 30cm below the most recent snow. With a little more effort and a few more hits on the ECT (ECTP 35 @ 60cm), the column failed near the bottom of the snowpack.

Region
Northern Madison
Location (from list)
Dudley Creek
Observer Name
Erich Schreier

Skier triggered wind slab in Hyalite

Overlook Mountain
Northern Gallatin
Code
SS-ASc-R2-D1.5-S
Elevation
9600
Latitude
45.40500
Longitude
-110.94200
Notes

From obs: "...We continued up and decided to stick to a ridgeline with trees in order to avoid the surrounding gullies which we believed may be cross-loaded. Near the top of the ridge (Around 9800') our options narrowed to either committing to climbing a gully or turning around, and after a couple hand shears we noticed the new snow was becoming stiffer and sliding easily on the crust so we ripped skins and turned around. 

Our route had one area of concern on the way down, which was a small gully between a cliff band. I made a ski cut towards the top since the terrain had (relatively) lower consequence and was able to release a wind slab roughly 4-6" deep. The deeper area to the right was the descent track from group members 2 and 3 after the wind slab had released."

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
S - Avalanche released within new snow
Problem Type
Wind-Drifted Snow
Slab Thickness
6.0 inches
Slab Width
30.00ft
Images
Skier triggered wind slab, Hyalite
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
20-21

From obs: "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." Photo: JR Mooney

Avalanche Details: Skier remote triggered deep slab near Mt Blackmore
Forecast link: GNFAC Avalanche Forecast for Sun Mar 28, 2021GNFAC Avalanche Forecast for Mon Mar 29, 2021GNFAC Avalanche Forecast for Wed Mar 31, 2021
Northern Gallatin, 2021-03-27
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    • Skier remote triggered deep slab near Mt Blackmore

    Mt Blackmore
    Northern Gallatin
    Code
    HS-ASr-R2-D2-O
    Elevation
    9500
    Aspect
    NE
    Latitude
    45.44070
    Longitude
    -110.99900
    Notes

    From obs: "Skied Mount Blackmore today. 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."

    From obs: "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... We confirmed that a beacon search was done to make sure no one was buried."

    Number of slides
    1
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Hard slab avalanche
    Trigger
    Skier
    Trigger Modifier
    r-A remote avalanche released by the indicated trigger
    R size
    2
    D size
    2
    Bed Surface
    O - Old snow
    Problem Type
    Persistent Weak Layer
    Slab Thickness
    90.0 inches
    Vertical Fall
    220ft
    Slab Width
    50.00ft
    Weak Layer Grain type
    Depth Hoar
    Images
    Deep Slab Avalanche in Blackmore Basin, skier remote triggered
    Skier remote triggered deep slab on Mt Blackmore
    Slab Thickness units
    inches
    Single / Multiple / Red Flag
    Single Avalanche
    Advisory Year
    20-21

    Skier triggered wind slabs Mt Blackmore

    Mt Blackmore
    Northern Gallatin
    Code
    SS-AS-R1-D1
    Elevation
    9500
    Aspect
    E
    Latitude
    45.44250
    Longitude
    -111.00100
    Notes

    From obs: "Observed a small skier triggered slide on the middle ridge of MT Blackmore today, skier was cutting across when it released."

    From obs: "Skied Mount Blackmore today. There was a lot more new snow than expected (6-8") and ridgetop winds were strong and gusty. Snow along the ridgelines and on E-facing slopes was touchy. Lots of cracking and collapsing. Saw 4 skier triggered slides on the E face between the Blackmore and Alex Lowe Basins. Most appeared to be wind slabs,..."

    Number of slides
    5
    Number caught
    0
    Number buried
    0
    Avalanche Type
    Soft slab avalanche
    Trigger
    Skier
    R size
    1
    D size
    1
    Problem Type
    Wind-Drifted Snow
    Images
    Skier triggered wind slab, Blackmore
    Wind slabs on Mt Blackmore
    Slab Thickness units
    centimeters
    Single / Multiple / Red Flag
    Multiple Avalanches
    Advisory Year
    20-21
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