Cornice triggered avalanche. 2 skiers skinning the Emmas ridge line headed east to Davenport Hill. At the section that released the 2nd skier took a little higher line on the skin track set by the lead skier putting the 2nd skier closer to the apex of the ridge and the cornice released. The cornice was very large and extended/broke further back on the ridge than expected (full conversation about the cornice potential was had by both skiers prior to traversing the ridge). The cornice took out layers of 2 older cornice and washed out all the snow from the upper very steep rocky part of the slope and may have taken out everything to the ground all the way to the bottom of the basin. Estimated size of the cornice was size of 2 and half SUV (length). **lesson learned/take away: heightened awareness of cornice potential. this cornice broke back much further than was judged.