Four skiers triggered an avalanche on Butch mountain that broke above them as they were ascending on skins. All four were caught and carried through trees, one was buried completely, two partially. The avalanche was approximately 300′ wide, 1-3′ deep, running about 800 vertical feet. It broke on a WNW facing mid-slope convexity where slope angles increased from around 30 degrees (location of skiers) to angles approaching 40 degrees at the crown. This avalanche resulted in serious injuries to 3 of the 4 skiers and killed 2 dogs. All 4 skiers were rescued by an extensive interagency effort.