Skier Triggered Avalanche in Middle Basin

Middle Basin
Northern Madison
Code
SS-ASu-R3-D2-O
Elevation
9400
Aspect
E
Latitude
45.33320
Longitude
-111.38300
Notes

We found this fresh skier triggered avalanche in Middle Basin today 1/5/19. East aspect. 9,400’ elev. It broke 1-2’ deep on weak, sugary facets. We had stable results in our stability tests (so did another group nearby), but this slide and recent reports of collapsing in the area indicate an untrustworthy and unstable, poor snowpack structure. 

This avalanche was triggered by the second skier down the slope. Nobody was caught.

Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Skier
Trigger Modifier
u-An unintentional release
R size
3
D size
2
Bed Surface
O - Old snow
Problem Type
Persistent Weak Layer
Slab Thickness
16.0 inches
Vertical Fall
75ft
Slab Width
35.00ft
Weak Layer Grain type
Depth Hoar
Weak Layer grain size
3.00mm
Weak Layer Hardness
F-
Slab Layer Grain Type
Decomposing and Fragmented precipitation particles
Slab Layer Hardness
4F
Slab Thickness units
inches