Remotely triggered avalanche Lionhead

Lionhead Ridge
Lionhead Range
Code
HS-AMr-R3-D2-O
Elevation
8900
Aspect
N
Latitude
44.71450
Longitude
-111.31800
Notes

On 2/16/24 we saw a fresh avalanche in Watkins Creek that we think was triggered remotely during the day by a group riding in a flat meadow above, where we saw their tracks at least 150 feet away (photo). This slide was 2-3' deep and 100-150' feet wide, breaking on old sugary snow. HS-R3/4-D2-O. We rode along the flat terrain above the avalanche and could feel our sled tracks punch through the supportable slab into weak snow at the bottom of the snowpack.

We felt a couple collapses while sitting on our sleds, and saw a couple long shooting cracks while riding. We dug a snowpit in Targhee creek on a northwest facing slope at 9,435'. We had an ECTP27 below a 2.5' deep slab, sitting on 1.5' of weak sugary snow.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Hard slab avalanche
Trigger
Snowmobile
Trigger Modifier
r-A remote avalanche released by the indicated trigger
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
32.0 inches
Vertical Fall
200ft
Slab Width
150.00ft
Slab Thickness units
inches
Single / Multiple / Red Flag
Single Avalanche
Advisory Year