In This situation I was spotting the snowmobiler that jumped off the cornice. the snowmobiler was able to ride out in front of the avalanche. The avalanche was sort of a delayed release. the snowmobiler that triggered the avalanche was well ahead of the slide. The snowmobiler that triggered hear the radio transmission that there was an avalanche and was able to turn around and see the snow still moving.

Slow moving Soft slab. In the picture taken from the bottom you can see the cornice the rolled down close to the little tree, about 100-125 feet from the crown. The tow of the slide was up the hill about 30-50 feet from the crown.