The three-time X Games champion nailed her second run to lead a 1-2 Canadian finish in the women's slopestyle event. Teammate Dara Howell won the silver as Canada raised its tally to nine medals on the week.
Turski, from Montreal, scored 89.6 points on the three-rail, four-jump course for the victory.
"It's really cool to be able to call myself a world champion," she said on a conference call. "I'm feeling really confident. It's also a great title to have going into the Olympics ... I'm just ready to keep rolling with the momentum."
Turski remained confident despite sitting in eighth place with a score of 14.2 after the first round.
"I don't really know how I pull it off, I just get in this mood where I am saying to myself, 'You know what, its not the end of the world if this doesn't work out,'" she said. "And somehow that gives me my flow and I just go with it and it's been working.
"But I sure hope I land some first runs soon, that would be way easier."
Howell, from Huntsville, Ont., had 85.6 points and American Grete Eliassen was third with 81.2, with both getting their highest score in the first run. Yuki Tsubota of Pemberton, B.C., was fifth.
Turski, 24, has added a unique trick to her repertoire that her team has dubbed the Turkey Roll. It's an off-axis jump with one-and-a-half rotations and she nailed it on her final run.
"I needed it if I was going to continue to win," Turski said. "It took me out of my comfort zone at first but all my hard work has paid off and now I can throw it out there when I need to, like today.
"And now I get to say I'm world champion out loud. I can't believe it — it's awesome."
With her medal, Turski has secured her Canadian Freestyle Method A provisional nomination to next year's Olympic team. The slopestyle discipline will make its Olympic debut at the Sochi Games.
The 18-year-old Howell, meanwhile, was overjoyed with her second-place result.
"Oh my goodness, I'm second best in the world," she said. "It's so awesome, I can't even believe it."
Thomas Wallisch of the United States won the men's slopestyle, beating James Woods of Britain. Wallisch scored 94.8 points in his second run, landing four jumps that earned 95 points and one that received 94.
Woods took silver with 91.2 points while American Nicholas Goepper overcame a poor first run to take bronze with 89.2.
J.F. Houle of Drummondville, Que., settled for an 11th-place result after falling on both of his runs.
Earlier in the week, the Canadian freestyle team won six medals in moguls and one in aerials.
"We're very excited for all of our new world championship medallists and our other athletes who performed to their peak, particularly given the young age of the team," Canadian Freestyle Ski Association CEO Peter Judge said in a release.
"Having world championship medallists this close to the Games will certainly give everyone confidence moving forward towards (Sochi)."
Competition wraps Sunday with the skicross events.
FIS freestyle action continues next week with a moguls event in Sweden.
With files from The Associated Press.