This hard slab slid on a melt crust that topped the Oct snow, about 15cm above the ground.  Since the Oct snow was likely only a white ribbon along the ridgeline, the avalanche was down to the grass within a few feet.  Facets below last week's rime event was our first suspect until we identified that layer 20cm above the bed surface.  At its deepest the crown measured 195cm from bed to top and nowhere was it less than 2'.  The bulk of the debis was deposited above the road cut, though the road was buried several feet deep too. 

Several snowmobile tracks that appeared to be from yesterday or perhaps Tues crossed within a few feet above the crown and we wondered if the sledders had remotely triggered the slide.