Swiss snowboarders Olivia Nobs and Mellie Francon have won silver and bronze at a World Cup boardercross event in Gangwon, South Korea.

The race was won by 18-year-old Norwegian Helene Olafsen. Switzerland's Sandra Frei was fifth.

Nobs and Francon, both 26, had dominated in qualifying but were unable to catch up with the young Norwegian, who got a good start.

Switzerland's male snowboarders lived up to expectations and were unable to get anywhere near the podium. Fabio Caduff was the best-placed Swiss, finishing in ninth.

Olafsen, a half pipe specialist, said she typically doesn't train to compete in boardercross, which has athletes jostling for position as they race down a slick course marked by jumps and tight turns.

But that didn't stop the 18-year-old from shining in Sunday's contest. "I don't understand it yet (but) I felt better yesterday," Olafsen said. "It was fun to ride and if I have fun, I do well."

The competition at Hyundai Sungwoo Resort in Gangwon Province is the first snowboard world championships held in Asia, with 614 athletes from 45 countries registered to compete in five disciplines: snowboardcross, parallel giant slalom, parallel slalom, half pipe and big air.