20-21

Natural avalanche in Y-couloir west side Bridgers

Bostwick Creek
Bridger Range
Code
HS-N-R2-D2-O
Elevation
8700
Aspect
NW
Latitude
45.79760
Longitude
-110.93800
Notes

Ski patrol had brief visibility on 2/7/21 to see a large natural avalanche, believed to have ran 2/7/21, on the northwest slopes of Saddle Peak on the West Side of the Bridger Range.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Images
Truman Gulch Natural Avalanches
Natural avalanche in Y couloir
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
20-21

Natural avalanahce (and collapsing) Specimen Creek

Specimen Creek
Southern Madison
Code
N-R4-D2
Elevation
8500
Aspect
SW
Latitude
45.02650
Longitude
-111.04800
Notes

From obs: "GNFAC, You’re never going to believe this, but there was tons of whumphing up in Specimen Creek today! There were a few avalanche classes there digging snow pits and getting unstable test results by the sounds of it. We saw a good sized natural on a steep SW facing meadow around 8500’, probably would call it R4D2 but it was hard to get a good look through the storm."

Number of slides
1
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
4
D size
2
Problem Type
New Snow
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
20-21

Skier triggered test slope (and collapses) Beehive

Beehive Basin
Northern Madison
Code
SS-ASc-R4-D2-O
Elevation
8000
Aspect
W
Latitude
45.34070
Longitude
-111.39100
Notes

On 2/7/21 skiers in Beehive reported: "Numerous large collapses, ECTP in several pits on mid-pack facets, and triggered a test slope remotely from flat terrain. It broke in the old snow, but towards to top, maybe 10cm below the interface with the last week’s snow. Propagated over 50m, crown depth 60-100 cm. Would be solid size 2 if the slope wasn’t 20m tall."

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
4
D size
2
Bed Surface
O - Old snow
Problem Type
New Snow
Slab Thickness
30.0 inches
Vertical Fall
40ft
Slab Width
150.00ft
Images
Skier triggered test slope Beehive 2
Skier triggered test slope Beehive
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
20-21

On 2/7/21 skiers in Beehive reported: "Numerous large collapses, ECTP in several pits on mid-pack facets, and triggered a test slope remotely from flat terrain. It broke in the old snow, but towards to top, maybe 10cm below the interface with the last week’s snow. Propagated over 50m, crown depth 60-100 cm. Would be solid size 2 if the slope wasn’t 20m tall." Photo: Sam H.

Avalanche Details: Skier triggered test slope (and collapses) Beehive
Forecast link: GNFAC Avalanche Forecast for Mon Feb 8, 2021
Northern Madison, 2021-02-08
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    • On 2/7/21 skiers in Beehive reported: "Numerous large collapses, ECTP in several pits on mid-pack facets, and triggered a test slope remotely from flat terrain. It broke in the old snow, but towards to top, maybe 10cm below the interface with the last week’s snow. Propagated over 50m, crown depth 60-100 cm. Would be solid size 2 if the slope wasn’t 20m tall." Photo: Sam H.

    Avalanche Details: Skier triggered test slope (and collapses) Beehive
    Northern Madison, 2021-02-08
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    • Bacon Rind

    Date
    Activity
    Skiing

    After a long drive south on which we were joined by a few enthusiastic Big Sky Skiers we found an empty pull of and lots of new snow at Bacon Rind. 

    We didn't dig any pits and kept things well below 30degrees. Here are a few high points:

    • Several whumphs, but all down in the first 500' vert from the car 
    • No Cracking or collapsing at higher elevations and no vis to see any activity
    • Didn't see obvious evidence that persistent weak layers are hair-trigger, but I am glad that with the rate and duration of loading that there was a warning today. There was more snow at Bacon Rind than I expected. 
    • Snowing S1-S2 through the day, ~3" through the day 
    • Occasional Moderate winds, but mostly light wind
    • About 20" settled on top of the sun crust formed last Monday and Tuesday, a new snow avalanche would be no joke at this point
    • High on Wind-loaded and Considerable elsewhere seems appropriate
    • Unrelated, we saw well over a dozen vehicles off the road including 3 semis with trailers. The roads weren't that bad, I guess we are out of practice

    Have a good forecast in the morning. 

    DZ

    Region
    Southern Madison
    Location (from list)
    Bacon Rind
    Observer Name
    Dave Zinn

    Texas Meadows Ridgeline

    Date
    Activity
    Skiing
    Region
    Bridger Range
    Location (from list)
    Texas Meadow
    Observer Name
    Aaron Schoening

    Specimen Creek

    Date

    GNFAC,
    You’re never going to believe this, but there was tons of whumphing up in Specimen Creek today! There were a few avalanche classes there digging snow pits and getting unstable test results by the sounds of it. We saw a good sized natural on a steep SW facing meadow around 8500’, probably would call it R4D2 but it was hard to get a good look through the storm, it was snowing S1-S2 all day with moderate west winds at the ridgetops. My skin track from the day before was completely gone, bummer. There was a solid 3” on our car when we got back to the trailhead.
    Psyched to be powder skiing!
    Spencer

    Region
    Southern Madison
    Observer Name
    Spencer Jonas

    Beehive

    Date

    In Beehive with Rec 1. Numerous large collapses, ECTP in several pits on mid-pack facets, and triggered a test slope remotely from flat terrain. It broke in the old snow, but towards to top, maybe 10cm below the interface with the last week’s snow. Propagated over 50m, crown depth 60-100 cm. Would be solid size 2 if the slope wasn’t 20m tall. Didn’t actually get very far from the trailhead for various reasons so never got eyes on anything else.

    Observer Name
    Sam H
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