Gallatin National Forest Avalanche Center

Triggered a collapse and whumph while breaking trail across convex terrain feature. Estimated 30-40 feet wide. Dug pit approx. 10-15 feet from trigger on edge of slope slightly uphill.

scores from 3 separate ects performed side by side across slope. *first test was ECTN21 @ 178 then propagated on 161cm with 3 extra hits after standard 30 taps.

Dug on flank, 75-100 feet below crown of SS-AMu-R2-D2-O, triggered 2/21/22, 2' deep, 3' max depth. There was a separate, snow-biker triggered fatal avalanche on 2/19/22 a couple miles south of here, similar aspect, elevation and size. Overall stability has improved since then, but not yet "good".

posses socks @300' above skiers left tube good powder w/no rime on top no drizzle layer found in middle difficult to break apart column after prying off!