went up for the mt buller couloir and decided against it as the high winds and large cornice was an obvious thing to avoid. ended up doing the next chute lookers left (bulls head couloir?). we experienced alot of variable conditions from deep facets, powder, ice, rock and bullet hard wind slab. at about half way up with a fast approaching weather system we opted to head down. once at the fan i ended up cutting into the fan of the main buller couloir, suddenly i heard a thunderous sound. as i straight lined / veered to skiers right trying to keep my speed the crown traveled faster then i was, while riding on big chunky blocks of sliding slabs i managed to cut out of the slide after surfing blocks for almost 100m. luckily i had alot of speed while this happened so i could stay semi afloat on the blocks. examining the slide from a far i triggered the slab on very thin section of a large wind slab pretty much on rocks that ended up setting the crown off about 20-30m above me. the crown ran about 150-200m across and the slide ran roughly 300m down slope coming to rest on a flat bench. crown depth looked to be about one foot in depth in general varying deeper and thinner with the snow pack. a very close call today that reminded me even if you are out of the terrain you think will slide there is always a possible chance of the more mellow slopes to slide also. in my opinion the fact i was riding with great speed is the reason i was able to escape and stay afloat even when riding in/ on the slide.