Stoke impeded judgement on Donner Peak

On our way up Donner Peak, skinning it from the West End neighborhood, we noticed large cornice breakage on Mt Judah, and other small crowns on Trestle and the Lincoln-Anderson ridgeline. Skiing down the Lake Run from Donner Peak, My partner and I were skiing just left of most of the tracks, and getting into some more complex, cliffy terrain. The chute is just above where the snowshed tunnel countouring Donner Peak disappears into the hillside, before reappearing where most Lake Run descents end up (at the large break in the tunnels). We approached a convex roll (red flag 1) which led to a 50ft wide chute with trees in the apron (2nd red flag, the terrain trap of trees in the potential slide path, which we had discussed before dropping in). My partner called his drop, and made his first turn on the convex roll, sending fractures in both directions, and releasing a large slab (crown height ~1-1.5'). I yelled to get his attention while he was making turns down the chute. He soon realized the slope was going, and pointed it out of the chute and into the trees, where he began being swept away by the debris into the trees. He ended up without injury, burried in the standing position up to his waist. I yelled for him to see that he was ok, and traversed around the chute, setting off another small slide on the next face over. The swirling snow from this debris made it to my partner, but none of the debris itself.