With light snow falling, competitors needed to work with the conditions while still pushing hard enough to earn a place in the top 12, with two runs to get the job done.
Starting strong with a left cork 900, Thomas showcased her unique style and trick variety as she made her way down the pipe.
Knowing she could tidy things up by adding the grab on her opening trick, she headed back to the top with room to improve.
With experienced athletes faltering — including China’s Eileen Gu, the Beijing Olympic gold medallist, losing a ski on her first run, and former world champion Kelly Sildaru looking to build on a conservative opener — a top 12 place was far from secure at this stage of qualifying.
The pace picked up on the second run as Gu landed her run to move safely inside the top 12 and several others increased their difficulty to climb the leaderboard.
By the time Thomas dropped in for her second attempt, she was sitting in 10th.
Putting down a clean, composed second run and tidying up the execution, she lifted her score to 77.50 but stayed 10th, good enough to book her ticket to the final round.
Thomas, who hails from Auckland, described her runs as "loose but lit".
"I’ve got a bit to clean up in finals. I’m happy I could show my spin on things," Thomas said.
"I’m super, super happy. Really proud of myself.
"I’m just really grateful for everyone who helped me get here and grateful for the team around me.
"Zoi [Sadowski-Synnott] and everyone who has competed this week has been such an inspiration to me, just how they carry New Zealand on their chest.
"It’s such a proud feeling as a friend and team-mate. They’re amazing."
Zoe Atkin, of Great Britain, topped qualifying with a best score of 91.50, while Gu qualified fifth with a score of 86.50.
The competition was paused for 15 minutes when Canadian Cassie Sharpe, who won halfpipe gold in 2018 and silver in 2022, fell and appeared to knock her head.
She received medical attention but still qualified third.
Heavy snow again forced organisers to change the schedule, with qualifying for the men's freeski halfpipe pushed back from Thursday evening to last night.
Kiwis Fin Melville Ives, Luke Harold, Gustav Legnavsky and Ben Harrington competed in the qualifying late last night (NZ time) and the final is scheduled for this morning. — Allied Media/RNZ
Women’s qualifying: Mischa Thomas, 77.50, 77, 10th.
7.30am: Finley Melville Ives, Luke Harold, Gustav Legnavsky and Ben Harrington (possible)
| 1. Norway | 16 | 8 | 10 | 34 |
| 2. USA | 9 | 12 | 6 | 27 |
| 3. Italy | 9 | 5 | 12 | 26 |
| 4. France | 6 | 8 | 5 | 19 |
| 5. Netherlands | 6 | 7 | 3 | 16 |
| 6. Sweden | 6 | 6 | 3 | 15 |
| 7. Switzerland | 6 | 4 | 4 | 14 |
| 8. Germany | 5 | 8 | 8 | 21 |
| 9. Austria | 5 | 8 | 5 | 18 |
| 10. Japan | 5 | 7 | 12 | 24 |
| 22. New Zealand | 0 | 2 | 1 | 3 |
