A large cornice fell (probably 8-10ft tall, 30ft long, and 6ft wide) while we were skinning along Emma's Ridge, right as we got to the Silver Fork Headwall. The cornice broke at the well traveled skin track which was about 6ft away from the lip of the cornice. The break was fast and silent, I mostly noticed because my left foot shifted when the cornice broke. No one was caught or fell with the cornice. The cornice fall then triggered a hard slab which broke on the rocks and across the headwall; and then slide the length of the short run into the flats. In the photo, you can see the different layers in the slab. We did not climb down to investigate, looks like it broke on an old weak layer given the thin snowpack over the rocks.