Came across an extremely large natural avalanche about 130 pm. Based on the amount of snow on the debris, estimated it ran between noon and 1. Visibility was poor, so we could not accurately see all that had avalanched, but likely encompassed most if not all of the NE facing terrain along a prominent subridge. The one flank of the avalanche we could look at showed that the slide failed initially as a wind slab, but quickly stepped down to the ground. Crown was around 6 feet deep. The portion that stepped to the ground is in a thin rocky area, and uncertain if the rest of the avalanche stepped down to the ground. Amount and depth of debris was truly impressive.

Photos below. Visibility limited anything better. Had some concerns for steep N-NE facing before the storm, but did not anticipate this large.