American snowboarding veteran Seth Wescott won the gold medal in what's been called the Olympics' most extreme sport. The boarder from Farmington, Maine, slipped into first place midway down the 3,100-foot chute and held off Slovakia's Radoslav Zidek for the win. The two were nearly side by side as they crossed the finish line.
Paul-Henri Delerue of France took the bronze.
Going into the games, Wescott was confident, CBS News' Manuel Gallegus reports.
"You need really quick footwork, really precise turns to get the job done and be fast. So it really kind of plays into my strengths," Wescott said.
Americans now have won all three gold medals awarded in snowboarding.
Also Thursday, the Winter Olympics got its first doping scandal when Russian biathlete Olga Pyleva was stripped of the silver medal she won three days earlier and kicked out of the games for doping.
In the Italian Alps, Estonian cross-country skier Kristina Smigun won her second gold of the week. And with Pyleva out of the women's 7.5-kilometer biathlon sprint, Florence Baverel-Robert of France was a surprise winner.
Later Thursday, Evgeni Plushenko of Russia was the favorite to take the men's figure skating gold after opening up a commanding lead in the short program on Tuesday. If all goes well for American favorite Johnny Weir, the U.S. will have another silver.
Medals also were being awarded in the women's skeleton and another event making its Olympic debut in Turin — speed skating team pursuit.
A hastily convened, three-member IOC panel found Pyleva guilty of a doping violation. She had tested positive for the banned stimulant carphedon in a urine test following Monday's race.
Nikolai Durmanov, head of the Russian Anti-Doping Committee, said a doctor who treated her for an ankle injury in January gave her an over-the-counter medication that did not list carphedon as one of its ingredients.
"This was 100 percent the physician's mistake," Durmanov said.
Martina Glagow of Germany, who finished fourth, will be awarded the silver. Albina Akhatova, Pyleva's Russian teammate, goes from fourth to bronze.
Further possible sanctions — such as a long-term ban from competition — are up to the International Biathlon Union.
"It's a bad thing that somebody is testing positive, but it's a good thing we got her," World Anti-Doping Agency chief Dick Pound said.
The head of Russia's biathlon federation, Alexander Tikhonov, said athletes have been told repeatedly only to use medications approved by team doctors.
"We warned them a thousand times," he told Russia's Itar-Tass news agency. "Take only medical formulas that are in the team and come only to our doctors. I have no idea where that doctor who treated Pyleva's foot injury came from."
Tikhonov maintained Pyleva used an "innocent" substance to accelerate healing and has no performance-enhancing properties.
"One has to admit that all should be blamed on our illiteracy and irresponsibility," he said.
The IOC has conducted 380 tests since the athletes' village opened Jan. 31; Pyleva is the first athlete to be caught by the IOC's most rigorous doping control program ever at a Winter Olympics. A total of 1,200 samples are being tested, a 72 percent increase over the number in Salt Lake City, where there were a total of seven doping cases.
In Pyleva's absence, Baverel-Robert crossed the line first, followed by Anna Carin Oloffson of Sweden and Lilia Efremova of Ukraine in third.
The race started in a heavy snowfall but the sun was shining and the San Sicario course turned slushy by the finish. Oloffsson crossed the finish line 2.4 seconds behind Baverel-Robert's time of 22 minutes, 31.4 seconds. Efremova was 6.6 seconds behind the surprise gold medalist.
In the final race of the snowboardcross, Wescott took the lead over silver medalist Radoslav Zidek of Slovakia with a deft passing move in the middle of the course and led the rest of the way, barely beating Zidek to the finish line. Paul-Henri Delerue of France took the bronze.
"I just knew if I was patient and confident that I'd reach the part of the course that I could work a little better, catch the speed on him," Wescott said. "Then coming into that one turn, I dove the inside line on him like clockwork. That's how it worked out."
In the women's 10-kilometer classical cross-country race, Smigun, who won the 15K pursuit on Sunday, took the lead by the 7-kilometer mark and finished in 27:51.4, a commanding 21.3 seconds ahead of World Cup leader Marit Bjorgen of Norway. Another Norwegian, Hilde Pedersen, took the bronze.