We triggered a large avalanche on an E/SE facing slope around 12,250'. It is unclear exactly what triggered it- we were skinning up the ridge and I reached over and probed to the ground (around 1m) with my ski pole right as the avalanche released about 10 meters out on the slope. One of my partners was skinning ahead of me so it's possible his weight was the trigger, although he was on pretty hard snow back on the ridge so I'd like to think I tickled the weak layer with my pole and it propagated from there. The crown averaged about 1-2 feet and appeared to have broken on the old/new snow interface.

We skied down from Copper Mountain on slightly less steep terrain to looker's right (more SSE) and found a couple inches of unconsolidated snow on old breakable crust. Skiing in the near treeline zone on east and northeast aspects produced numerous cracks and collapses but the terrain was not steep enough to produce avalanches.

Graveline gulch to the summit of Copper Mountain