YAMANOUCHI, Japan (AP) _ The United States took bronze medals in men's and women's halfpipe events as snowboarders rallied behind the Canadian rider stripped of a gold medal for marijuana.

Under a heavy downpour, Germany's Nicola Thost and Switzerland's Gian Simmen won the golds. The men's bronze went to 18-year-old Ross Powers of Londonderry, Vt., while Shannon Dunn of Steamboat Springs, Colo., won the women's bronze.

Simmen twisted, flipped and spun down the snow trough _ his hat flying off during one midair twist _ for a two-run total of 85.2 points.

Norway's Daniel Franck won the silver with 82.4 points ahead of Powers' 82.1. Todd Richards, the other American to reach the final, slumped to 16th with 69.6.

Thost captured the women's event with 74.6 points. Norway's Stine Brun Kjeldaas won the silver in 74.2 and Dunn, the leader going into the final run, finished with 72.8.

Dunn fell out of competition for the gold when she lost her balance on her last run, sat back and nearly fell. She recovered to finish the run but lost valuable points.

But the results took a back seat to the controversy over the disqualification of Ross Rebagliati, winner of Sunday's giant slalom.

The International Olympic Committee stripped Rebagliati of his gold medal after he tested positive for traces of marijuana. Rebagliati, who was appealing the decision, said the traces must have come from second-hand smoke at a party in Canada last month.

After completing his first qualifying run, Canadian rider Michael Michalchuck unfurled a sign reading: ``Ross is the champion. Give him the gold back.''

Michalchuck said he wrote the slogan on a cloth hotel napkin the night before. His girlfriend handed it to him at the bottom of the course.

``I believe in Ross,'' Michalchuck said. ``He's the gold medalist. No one can deny him. He believes he hasn't done anything wrong. He's an athlete. He's an Olympic athlete. He is the champion. No one should be taking that away from him.''

In the competition, riders rode back and forth down the chute _ measuring 120 meters long and 15.4 meters wide, with walls 3.5 meters high _ performing a series of skateboard style maneuvers with names like McTwist, Alley-oop, Backside, Indy Grab, Stale Fish and Mute Grab.

The competitors were judged for eight to 10 ``hits'' or maneuvers, including aerial rotation, height, landing and technical merit.

The runs were accompanied by an eclectic mix of music, ranging from rock, reggae, hip hop and grunge. The tunes included songs by Jimi Hendrix, Oasis, Beck, Queen, Blondie, Bob Marley and Jim Morrison.

Two American women, Dunn and Cara-Beth Burnside, qualified for the final after two runs. Burnside finished fourth with 72.6 points. Michele Taggart and Barrett Christy failed to make the final.

In the men's event, Powers and Richards qualified for the final, but Ron Chiodi didn't.

The men's competition was missing the sport's superstar, Norway's Terje Haakonsen, who boycotted the games in protest against the Olympic establishment.

One by one, after completing their twists and turns down the snow chute to blaring rock music, the shredders ripped the IOC's decision to strip Rebagliati.

Michalchuck claimed the Canadian snowboarders were ``misinformed'' about the doping-control system, saying they didn't know the tests covered marijuana.

``I don't smoke marijuana,'' he said. ``Ross doesn't smoke marijuana, but when you are around marijuana, it can be in your system. He's innocent and should be cleared.''

Another Canadian, Maelle Ricker, said: ``He's a fair competitor. He didn't cheat.''

``He still won the gold medal to me,'' said Burnside. ``Everyone's just furious about it. It's not affecting his performance, c'mon. They're kicking people out for cough medicine.''

``It's ridiculous,'' Taggart said. ``There should have been some more investigating before they went and made it a public thing. Once they start testing other athletes, they're are going to be a lot more situations that come up. I just feel bad for Ross.''

Anita Schwaller of Switzerland said Olympics organizers were making a big mistake.

``It's so ridiculous,'' she said. ``No one's riding faster (because of drugs). It's not good for the image of the sport. It's not the riders who wanted to be in the Olympics. They wanted us. It's a more liberal sport.''

The snowboarders, competing in the Olympics for the first time, said they were angry that their counterculture sport was being associated with drug use.

``It's happened in other sports,'' Dunn said. ``It's not the sport. It's a person. You can't stereotype all snowboarders. All the people I hang out with in snowboarding don't do any drugs.''