20-21

Natural new snow slabs in YNP near Cooke

Other place
Out of Advisory Area
Code
SS-N-R2-D2
Elevation
8500
Aspect Range
N,S,E
Latitude
45.65530
Longitude
-110.55800
Notes

These slides were observed in Yellowstone National Park on 2/7/21.

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Problem Type
New Snow
Images
Natural in YNP 2 - 7 Feb
Natural in YNP - 7 Feb
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
20-21

Large explosive triggered, and naturals on road cuts, at Y.C.

Yellowstone Club
Northern Madison
Code
HS-AEc-R5-D3-O
Latitude
45.23110
Longitude
-111.44100
Notes

From YCSP: "We’ve had more snow and SWE in the past 5 days than we had in all of January. Avalanche mitigation today produced avalanches running full path at the new snow/old snow interface for most of our paths.... Some of our lower ridge avalanche terrain climaxed for the 2nd time this season. Our first round of mitigation got a few paths to climax, but the teams didn’t feel confident with the initial results.... They went back out with more explosives and were able to produce an avalanche that ran 400’ wide, with a 6-10’ crown, running close to the ground. This is wind loaded terrain. It’s also perhaps the largest crown I’ve seen on these paths and one of the few times I’ve seen it climax more than once.

I took a drive at the end of the day and captured a few photos of road cuts at the YC that slid today."

Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
An explosive thrown or placed on or under the snow surface by hand
Trigger Modifier
c-A controlled or intentional release by the indicated trigger
R size
5
D size
3
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
72.0 inches
Images
Natural avalanche on road cut 2
Natural avalanche on road cut
Large explosive triggered slide at Y.C.
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year
20-21

Natural avalanche on Cedar Mtn.

Cedar Mtn.
Northern Madison
Code
U-N-R2-D2-U
Aspect
E
Latitude
45.22680
Longitude
-111.51200
Notes

A patroller a the YC saw a slide on some of Cedar Mountain’s lower east facing terrain on 2/7/21.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Unknown
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
U - Unknown
Vertical Fall
200ft
Slab Width
100.00ft
Images
Natural avalanche on Cedar Mtn.
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
20-21
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