Korean snowboarder Choi Gaon poses with her gold medal from the International Ski Federation World Cup event in Copper Mountain, Colorado, after arriving at Incheon International Airport, west of Seoul, in this Dec. 18, 2023 photo. Yonhap

The ongoing Winter Youth Olympics in South Korea will be without one of the host country's biggest stars, as snowboarder Choi Gaon was ruled out of the competition Sunday with a lower back injury.

The Korea Ski Association (KSA) announced Sunday that Choi, 15, will sit out the Winter Youth Games in the eastern province of Gangwon, after hurting her back during a training session at the International Ski Federation (FIS) World Cup in Laax, Switzerland, the previous day.

Choi had been considered a gold medal favorite in the women's halfpipe at the Youth Olympics. Her event is scheduled for the final day of the competition on Feb. 1.

Choi captured her first senior World Cup title in her debut last month. In Laax, Choi had ranked second in qualification with 94.00 points, behind only the two-time Olympic champion Chloe Kim (97.00 points).

However, Choi fell and injured her back while training for the final and missed the medal competition. She finished in sixth place.

Choi was transported to a local hospital, where a doctor recommended surgery, according to the KSA.

In March 2022, Choi won the halfpipe gold at the FIS Junior World Championships, and then in January 2023, she became the youngest superpipe champion in X Games history at 14 years and three months.

Choi will miss her X Games title defense later this month, which would have been her final prep event before the Youth Olympics.

Without Choi, South Korea's best Youth Olympic medal hope in snowboard rests with Lee Chae-un in the men's halfpipe.

Lee, 17, finished seventh in Laax with 83.50 points in the halfpipe Saturday. The 2023 world halfpipe champion won a World Cup bronze last month in Colorado. (Yonhap)