Glacier skier accidental Sz 1.5

Skier accidental Sz 1.5 windslab. Skier 1 skied slope from top with no incident. Skier 2 entered slope from top and on 3rd turn initiated avalanche. Tried to ski out skiers left but was faced with a cliff wall and knocked off feet. Was able to stand up and ski out when it stopped. Contemplated pulling airbag but decided not to. No lost gear or injuries. Avalanche initially was small 10cm crown, 3m across however propagated to a deeper part of slope up to 50cm and around cliffs. Winds light out of north. Temp -10. Sky clear. Approach route was up steep south southwest meadows and low angle alpine west through north. 10-20cm ski pen on melt freeze crust. Few small pockets of soft windslab, 10cm deep, 1m across. No evidence of recent slab avalanches. 1 natural loose dry, Sz 1 on south aspect running far. On lower part of the descent through treeline group did notice up to 40cm snow on top of meltfreeze crust on west aspect.