US snowboard star Kim stays on track for Olympic hat-trick
Kim, who had an injury-disrupted build-up to the Milan-Cortina Games, shot to the top of the qualifying times with a score of 90.25 on her first run.
Japan's Sara Shimizu, who won silver at last year's world championships, was second on the charts after posting 87.50 in the second of her two runs.
America's Maddie Mastro was in third spot with a score of 86.00, followed by another Japanese athlete, Rise Kudo (84.75).
Chinese veteran Liu Jiayu, the silver medallist at the 2018 Pyeongchang Games, landed heavily towards the end of her second run, lying motionless on her back in the snow.
Officials raced towards her and she received lengthy medical treatment before being towed away on a stretcher, with her condition unknown.
Two-time defending champion Kim, 25, has dominated women's halfpipe since the 2022 Beijing Games, winning X Games gold in 2024 and 2025 and claiming her third world championship title last year.
But her build-up to the Games in Italy were badly disrupted by injury, including a dislocated shoulder last month while training in Switzerland.
Ester Ledecka, from the Czech Republic, and Austria's Anna Gasser both blew their chances of becoming the first snowboarders in Olympic history to win three titles in a row earlier in the Milan-Cortina Games.
But Kim will be favourite to make history in Thursday's final.
In the halfpipe, competitors perform a series of tricks while snowboarding down a slope with a semi-cylindrical shape. They are scored on the breadth and difficulty of the jumps.
The top 12 qualifiers advanced to the final based on their better run of their two runs.