Katerina Hoskova of the Czech Republic won the gold medal after earning 138.58 points during the 25-gate run without any penalties. Nanqin Cen of China posted a faster time but was assessed four penalty seconds and took the silver at 140.13. Katarina Macova of Slovakia was third.
"I was really happy with my finish," said McGee. "However, in training I was going even faster, and I think I could have been on the podium if I had had a good run. It was a hard course for all of us, everyone struggled, but I am happy."
McGee, who qualified 10th in the morning semifinal, climbed to sixth with 179.45 points. She was assessed four penalty seconds near the bottom of the course.
"The level of competition in the C1-W class has risen substantially, which is huge for our sport and our push to get on the Olympic schedule," she said.
Sindy Audet of St-Eustache, Que., was 19th in the semifinals and did not advance.
The news wasn't so good for Canada in the Olympic events as it fell short of earning quota spots. The next opportunity will be at the Pan Am Championships in March 2012.
In semifinals, Paul Manning of Calgary and John Hastings of Ottawa were 35th and 40th in K-1 and Cameron Smedley of Dunrobin, Ont., was 30th in C-1.