22-23

Natural avalanche at Frazier Basin

Frazier Basin
Bridger Range
Code
SS-N-R1-D1.5
Elevation
9000
Latitude
45.92330
Longitude
-110.98000
Notes

From IG message 3/11/23: "...yesterday, at Fairy Lake, very windy and this slid naturally sometime between when we got to the area at noon and 3oclock. There was also a smaller natural wind slab in the northern bowl with arrowhead. Observed wind loading all day."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
1
D size
1.5
Problem Type
Wind-Drifted Snow
Vertical Fall
800ft
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Very large natural on Fisher Mtn.

Fisher Mtn.
Cooke City
Code
HS-N-R3-D3-O
Elevation
10200
Aspect
E
Latitude
45.06610
Longitude
-109.95900
Notes

From obs "We rode up Lulu Pass at 8AM on 3/11/23 and saw the debris from a large D2.5-3 avalanche on the SE face of Fisher Mtn. Similar slide path to the large avalanche on Fisher earlier this season."

From GNFAC 3/12: "Today we rode north of Cooke City and looked at recent natural and Human-triggered avalanches. The slide on Fisher Mtn. was very large and appeared up to 10 feet deep. It had much more volume in the debris than the slide that was triggered on this same path in December."

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
3
D size
3
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
72.0 inches
Vertical Fall
600ft
Slab Width
700.00ft
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Several avalanches observed near Cooke

Mineral Mountain
Cooke City
Code
N-R2-D2-I
Elevation
9700
Aspect Range
ENE, E, SSW
Latitude
45.03030
Longitude
-109.99800
Notes

From obs 3/11/23:

Several avalanches observed D2-D2.5.
Crown depth 80-120cm
ENE @ 10,000’

E @ 9700’

SSW @ 8800’

Number of slides
3
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
I - Interface between new and old snow
Problem Type
Wind-Drifted Snow
Slab Thickness
36.0 inches
Snow Observation Source
Slab Thickness units
inches
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

Natural avalanches near Cooke

COOKE CITY
Cooke City
Code
N-R2-D2
Elevation
9500
Aspect Range
NW, E
Latitude
45.02020
Longitude
-109.93800
Notes

PHotos attached of some natural avalanches near Cooke City today (3/11/23).

Avy1: NW aspect, around 10,000'. (This starting zone also avalanched in a similar way around Feb. 21).

Avy2: E aspect, around 9,000'.

Number of slides
2
Number caught
0
Number buried
0
Trigger
Natural trigger
R size
2
D size
2
Problem Type
Wind-Drifted Snow
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year

3 large avalanches at Lionhead

Lionhead Ridge
Lionhead Range
Code
HS-N-R3-D2.5
Elevation
9300
Latitude
44.71450
Longitude
-111.31800
Notes

From IG message: "3 different slides lionhead area. One was very big the run out was 20 feet tall and quarter mile long"

Number of slides
3
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Natural trigger
R size
3
D size
2.5
Problem Type
Wind-Drifted Snow
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Multiple Avalanches
Advisory Year