Hi Jbecker, 10hrs sounds like you must be in great shape. We are looking to attempt the combo from Happy Isles next week. I've done Half Dome alone twice; took about 8-8.5 hours roundtrip, coming from sea level in NY with a day or two to acclimatize. I am anticipating 13-14hours for the trip, sounds reasonable? Is there anything you would recommend based on the current conditions? Do you thiby nyker - General Discussion