He definately locked up the front wheel, dirt or not. You can see he has already landed the wheelie and the bike is stable, moving in a straight line, he's off the throttle. Then the front wheel slides out to the right, only thing that could cause that is locking up the front. Maybe dirt, maybe not, but clearly rider error. He must have missed that whole pay attention to road surface part

Noob mistake handful of front brake in the dirt. His get off had nothing to do with wheelies. Wheelies are easy to do on a big bike. I have only had 2 unintended wheelies since I have been riding. Power wheelies come up slowly and are where you generate lots of speed because as the name implies you have to be powering forward hard on the throttle. Clutch wheelies are best done in second gear, they come up extremely fast. Personally I don't care to do them.

yea you see dust and shaZam! fly before he goes down...but thats part of knowing your riding area... especially if you are riding back in forth in a short distance...but hey as long as he didnt hurt anybody but himself i dont care what he wears