Ice Climber triggered avalanche in Avalanche Gulch, Hyalite

Hyalite - main fork
Northern Gallatin
Code
SS-AFu
Elevation
9200
Aspect
W
Latitude
45.44720
Longitude
-110.96200
Notes

A first person account: "Human triggered avalanche at (estimate) 1:30pm from upper 'Avalanche Gulch' by one party descending from 'Dribbles'. Climber on second moderate pitch of 'Avalanche Gulch' swept but saved by screw placement from going over pitch 1 of Avalanche Gulch. No injuries, no burials, and both parties reconvened at base of Avalanche Gulch to assess the event. All parties descended at 3pm."

More info:

We were looking around for 'Responsible Family Men' and caused the avalanche crossing the gully perhaps ~200+ ft up from the snow ramp on AG. We immediately hoofed it downslope after the sl slide ccurred to see if there were folks caught up in it, and assist if at all possible. Thankfully it went as it did. I would estimate that the wind around Dribbles was 5-10, gusting 20-25. 
 
Number of slides
1
Number caught
0
Number buried
0
Avalanche Type
Soft slab avalanche
Trigger
Foot penetration
Trigger Modifier
u-An unintentional release
Problem Type
Wind-Drifted Snow
Vertical Fall
400ft
Slab Thickness units
centimeters
Single / Multiple / Red Flag
Single Avalanche
Advisory Year