Pro Skier Kyle Smaine Killed In Avalanche, Dead At 31

Professional skier Kyle Smaine -- who won gold at the 2015 Freestyle Ski and Snowboarding World Championships -- has died in a terrible ski accident, his family announced.

He was 31.

Smaine was in Japan skiing ... a place he enjoyed frequenting this time of year due to the "unbelievable snow quality," something he talked about on social media before the accident.

Smaine was on the trip with photographer Grant Gunderson, who recounted the frightening events in an emotional Instagram post, calling it his "absolute worst nightmare scenario."

Grant says he was tired so he decided to go down the mountain and rest. But, Kyle wanted to keep skiing. Gunderson says things took a turn for the worst when another skier triggered a large avalanche that threw Smaine 50 meters, and buried him, killing the 31-year-old.

Gunderson says rescue officials -- "two mountain guides and 4 or 5 emergency doctors" -- did everything they could to save Smaine, and another man who is yet to be identified, but tragically there was nothing they could do to save the men.

A spokesperson for the U.S. Embassy in Tokyo said they're "aware of the incident in Nagano Prefecture" and are working with local authorities.

Gunderson, crushed over the loss of his friend, said Smaine's death is something he will be "rehashing" for the rest of his life.