Rider triggered avalanche on Ledge Saddle

Observed three riders skinning across a slope and trigger an avalanche. A very large whumpf was heard and you could feel the snowpack settle. The third person of the group was taken for a ride but thankfully uninjured and able to self extricate. Snow quality was a bit of everything throughout the day. Excellent in sheltered areas. Very wind affected in some. Breakable crust in others.