did you have a helmet on at the time?

No. I'll be getting one (and some body armour) before I go out next -- I also bruised a rib earlier in the day. Pulling wheelies in powder's only good as long as the powder doesn't run out .

he literially did a cartwheel with his head

Sounds kinda similar. I came out of some powder, hit some ice, caught an edge, and landed full length, face first, in another pile of powder. Somehow, my board came over my back and I kicked myself in the back of the head. I'd had the edges sharpened the day before, too.