Sounds very similar to what I heard camping in the Cacades near Cle Elum, Wa. It scared the crap out of me and was unlike any animal I have ever heard before. Definitely creepy and not any of our known animals in the forest. King 5 news even had sound recorders out and recorded it and it was the exact sound I heard, they had a wildlife biologist put it in their database of sounds and it came up as an unknown.