Thanks to some expert opinions I think we can close the door on this one.
I'd like to back off my total snow fall argument as well. While Mount Washington may get more snow than places in Colorado, the nature of the snow storms is entirely different. In CO you can get a 15 inch storm, then a week of clear cold weather, then another 15 inch storm. All adding to cornice growth. In NH you can get a 15 inch storm, then its followed by fog, riming, rain, and bitter cold. Two weeks later it snows another 15 inches, but the process must begin again and this time the snow surface is uncondusive to cornice growth.
New England...not a happy place for cornices.