Lionhead Range

On Sawtelle Peak, Island Park, when the clouds lifted we could see a crown of a snowmobiler triggered slide that occurred yesterday. It broke on the buried surface hoar and facets about 1.5 feet under the surface. Recent snow and wind-loading has created dangerous avalanche conditions. Photo: GNFAC

Island Park, 2024-01-19

An avalanche and instability

Date
Activity
Snowmobiling

We dug pits and rode on Sawtelle Peak. At 9,100 feet we had unstable test results (ECTP13 x 5; ECTP10 x2; CT4, Q1). When the clouds lifted we could see a crown of a snowmobiler triggered slide that occured yesterday. It broke on the buried surface hoar and facets about 1.5 feet under the surface. Recent snow and wind-loading has created dangerous avalanche conditions.

The avalanche:

44.55581, -111.45085
El 9,286'
 
HS - 143 cm
Surf hoar 96-95 cm
Slab was 18-24" deep
Not really wind loaded, but it looks like winds wrap around that face.
About 150' wide
about 300' vertical
Region
Island Park
Location (from list)
Sawtelle Peak
Observer Name
Doug Chabot

Multiple Remote Triggered Slides at Lionhead

Lionhead Ridge
Lionhead Range
Code
SS-AMr-R1-D1.5
Latitude
44.70260
Longitude
-111.36200
Notes

From facebook message: "Multiple remote triggers across this slope."

Up Targhee Creek, near Lionhead Ridge. 1/18/24

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
1
D size
1.5
Vertical Fall
50ft
Slab Width
30.00ft
Snow Observation Source
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year

Remote triggers at Lionhead

Date
Activity
Snowmobiling

From facebook message: "Multiple remote triggers across this slope."

Up Targhee Creek, near Lionhead Ridge. 1/18/24

Region
Lionhead Range
Location (from list)
Lionhead Ridge
Observer Name
Ryli Schlueter

Lots of Cracking, Taylor Fork

Date
Activity
Snowmobiling

From FB: Taylor’s Fork today, 8-10 inches of new snow last night. A few small slides but tons of cracking.

Region
Southern Madison
Location (from list)
Taylor Fork

Collapses and cracking at Lionhead

Lionhead Ridge
Lionhead Range
Code
Latitude
44.71450
Longitude
-111.31800
Notes

Rode up Denny Creek and out along Lionhead Ridge through Watkins Creek to the divide with Targhee Creek. Saw evidence of numerous older avalanches along the ridgeline and in lower steep meadows that likely broke last week (1/10-1/11). The crowns of these slides were blown in, but would estimate they generally broke 1-2 ft deep. Some broke quite wide ~1000 ft. Saw a couple smaller slides that looked to be a bit fresher as well. 

Got a number of collapses and shooting cracks as we rode today, shooting out 20+ ft. 

Stopped and dug a pit at the crown of an avalanche that broke on the north end of ski hill (likely during last weeks warning). Broke ~1 ft deep, 50 ft wide and ran 100 vertical. Another similar slide broke at the same time on the south end of ski hill. Today, we got an ECTP12 on the surface hoar about a foot deep.

The snowpack remains unstable and human triggered avalanches (including remote triggers from a distance) remain likely. Expect the danger to rise as it snows over the next couple days. 

Number of slides
0
Number caught
0
Number buried
0
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Red Flag
Advisory Year