Skier triggered avalanche on Donner Peak

We were skiing down from the north side of Donner Peak and observed around 6-12 inches of fresh storm snow without evidence of wind slabs on the slopes we skied. I approached a slope that was steep enough to trigger an avalanche, but based on conditions observed above and the forecast, we felt safe. We judged the terrain to be "below treeline" based on its lower elevation and tree density. I approached the slope cautiously from the top and observed that the snow was denser and more wind affected than what we had skied above. As I skied onto the upper section of the slope I triggered a small wind slab approximately 20ft wide and 40 ft long, maybe 6-12" deep. I was not caught in the slide and was able to cut back across the smooth slide surface back to safer terrain.