Sterling AST 1

Obs from AST 1 this past weekend (Jan 8th) at Sterling Snowmobile Area. Saw 1 size 2.5 and 1 size 1.5 from steep, convex terrain near ridge-top on Portuguese Hill. SW aspect at ~1450 m. Larger avalanche initiated in windslab and stepped down to persistent weak layer, suspect Jan 25 surface hoar. Reports from Facebook indicate avalanches were rider triggered. We primarily rode previously tracked terrain.