I've had cow elk "alarm" bark at me a couple of times - usually it's one bark, very loud and deliberate. What's demonstrated in the video is a lot calmer (in sound and the elk's posture) than that.
Re: the moose roar - at some point, one of us should record audio of it to share. I've heard it only once, many years ago. It hard to describe, almost like a moose ate a lion for lunch with grizzly for dessert. Very cool sound, and, frankly, a bit terrifying.
