Olympic medal-winning snowboarder Mark McMorris has broken his leg while at an event in California.

McMorris, who's from Regina, fractured his right femur on Sunday, the second day of the Air + Style snowboarding event in Los Angeles.

A video posted on Twitter showed McMorris landing after a jump, then falling hard and tumbling several times. It ends with McMorris clutching his legs.

"It's a pretty helpless feeling. Of course, you never want to see anyone get hurt, but when it's your own son there. I was able to get out and up to him right away. They had him off the snow and on a cart so I've been with him the whole time ever since," said Mark's father Don McMorris.

McMorris will be undergoing surgery to have a nail placed in his fractured femur to help it heal. It is expected to take six months for a full recovery.

"He's disappointed. He was looking forward to finishing out what had been a very good start to his season with two or three more contests around the world," said the elder McMorris.

"He was looking forward to finishing strong, but he'll have to wait until next year now."

McMorris won a bronze medal at the Olympic games in Sochi, Russia, in 2014, and is considered one of Canada's best hopes for gold in 2018.