Report 422: Campers hear possible vocalizations in the Okanogon Nat. Forest

Myself and two friends camped out at the Klipchuck Campground in the Okanagon Nat. Forest, just west of Mazama, WA. We had hiked up to Driveway Butte that day, and had not seen any other people or recent sign of any one.  In addition, we were the only people at the campground.  It was quite cold that night, so I was awake for a good portion of the night. At around 2 or 3 A.M.  I heard a loud yelling noise coming from the ridge to the north of us. It sounded like a very large man yelling at the top of his lungs. It did not have that voice-like quality of a person though. Several minutes later, I heard it again. Next morning, my friend who had been sleeping in the back of his pickup mentioned it, and described the incident in almost the exact way I remembered it. He was so startled by the noise, that he pulled his remote car horn beeper out of his pocket, and was ready to blast the horn if anything happened.  I have spent years in the backcountry of the West, and never heard anything like it.