Arresting with a Whippet

Sean moves off the left side of the rim of the couloir and traverses onto the steep face and preps for the first turn when - unbelievably his tail washes out, starts a backwards fall down the fall line and starts a slow, inevitable and unstoppable end-over-end roll. 

Yipes, scary account!
But just curious: tail of . . . snowboard? ski mounted tele? ski mounted AT?

Jon. S - your color added: I was snowboarding and Sean was on AT. I believe I was on a Burton 162 Custom and Sean on Tua's (with the little s-turns down the center). I think I was wearing black and sean red. (tongue firmly in cheek)

Okay, thanks.
In all seriousness, the reason I asked was that many of the skiers I see using Whippets for the descent are in one of two opposite ends of the spectrum:
-- truly extreme skiers on truly extreme terrain
-- telemark skiers with very shaky skills for any kind of even moderately steep terrain