A dramatic video has emerged of a man falling off his snowmobile as he's going down a slope in Montana, in the Rocky Mountains.

The footage, shot with a helmet mounted camera earlier this month, shows the driver flying off his snow mobile after he hit a rock.

The filmer later wrote online: "I was having fun snowmobiling!

"Then I hit a rock and it launches my sled and sends me flying."
"But the best part is yet to come," he continued.

"The sled flips over and the throttle gets stuck at full throttle!"