Lionhead Range
Natural Avalanche Lionhead Ridge
Lionhead Ridge
Lionhead Range
Code
SS-N-R1-D1.5-O
Aspect
E
Latitude
44.71450
Longitude
-111.31800
Notes
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
1
D size
1.5
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
18.0 inches
Attached Videos
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
Riders on Lionhead Ridge spotted this natural avalanche that occurred on January 21.
Avalanche Details: Natural Avalanche Lionhead Ridge
Lionhead Range, 2024-01-21
Natural Avalanche Ski Hill
Ski Hill
Lionhead Range
Code
SS-N-R2-D2-O
Elevation
7950
Aspect
E
Latitude
44.70160
Longitude
-111.29300
Notes
A natural avalanche broke on January 21 on Brady's Slope on Ski Hill. Walking to look at the avalanche, we triggered a large collapse and shooting cracks. We dug a pit nearby and got very unstable test results (ECTP4) on a layer of 15-20 mm surface hoar buried 18" deep. Avalanche width and vertical fall were estimated based on Google Earth measurements.
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Natural trigger
R size
2
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
18.0 inches
Vertical Fall
300ft
Slab Width
200.00ft
Weak Layer Grain type
Surface hoar crystals
Weak Layer grain size
15.00mm
Weak Layer Hardness
F-
Slab Layer Grain Type
Precipitation Particles
Images
Attached Videos
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year
This natural avalanche failed the morning of January 21 on a steep slope at Lionhead. Photo: GNFAC
Avalanche Details: Natural Avalanche Ski Hill
Forecast link: GNFAC Avalanche Forecast for Mon Jan 22, 2024
Lionhead Range, 2024-01-21
Forecast link: GNFAC Avalanche Forecast for Mon Jan 22, 2024
Very poor stability, and avalanches
Date
Activity
Snowmobiling
There was low visibility at Lionhead with a thick fog engulfing the ridge. We rode to Ski Hill and dug a pit on the south end. As we approached our pit site we noticed a recent avalanche on the steep center section of ski hill. It looked natural, possibly rider triggered in the last 24 hours, 14-18" deep, 225' wide, 200' vertical. SS-R2-D2-O.
Our snowpit had a layer of well-preserved 10-20mm surface hoar below 14" of snow (measured 2.45" SWE in 14" slab). Below that was soft facets, another layer of surface hoar, and more soft facets. We got ECTP4, and PST22/100end on the upper layer of surface hoar. The nearby avalanche probably failed on that surface hoar layer.
We went to look a little closer at the avalanche from a low angle (25 degree) slope above. While approaching we had a large collapse and shooting crack.
A group of riders in the parking lot saw a similar depth recent avalanche a little further up the ridge.
The snowpack is very unstable and avalanches large enough to bury or injure a person are likely to be triggered on any steep slope.
It was snowing lightly all day with calm wind and overcast to foggy skies.
Region
Lionhead Range
Location (from list)
Lionhead Ridge
Observer Name
Alex Marienthal
ECTP 11
Date
Activity
Snowmobiling
Snow warmed up significantly and felt heavy compared to a few days ago. Dug a snow pit on on an easterly slope. ECTP 11. Didn’t notice as much cracking as a few days ago.
Region
Lionhead Range
Location (from list)
LIONHEAD AREA
Observer Name
Travis Hansen
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
Avalanche Details: Snowmobiler triggered slide, Island Park
Island Park, 2024-01-19
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
Avalanche Details: Snowmobiler triggered slide, Island Park
Forecast link: GNFAC Avalanche Forecast for Sat Jan 20, 2024
Island Park, 2024-01-19
Forecast link: GNFAC Avalanche Forecast for Sat Jan 20, 2024