Snowboarding, the IOC's petition to global counterculture, will be making its fourth appearance as part of the Olympic Winter Games program. Thanks to an expanded slate of events and a cast of colorful characters, snowboarding was easily the breakout sport of the 2006 Torino Games. Four years later, here's a closer look at the top storylines to watch in Vancouver:

America's eminent domain
In Torino, the United States had its most successful Winter Games ever on foreign snow and ice, winning 25 medals. Snowboarding and speed skating led the way for the U.S. with seven medals each. In snowboarding, the Americans' strength lies in the halfpipe, though they proved to be nearly as imposing in snowboard cross. At the past two Olympics, the U.S. has collected eight of the 12 medals awarded in halfpipe, including all four golds and three of the four silvers. In 2010, the U.S. has the talent and the depth to sweep both events. Where the U.S. stands in the overall medal count will depend largely on the success of the riders at the Cypress venue.

Shaun White lived up to his advanced billing to claim Olympic halfpipe gold in Torino.

Shaun White, ladies and gentlemen ...
A revelation at the 2006 Torino Winter Games,Shaun White won halfpipe gold in signature style. Performing to AC/DC's Back in Black, the then-19-year-old racked up a near-perfect 46.8 points in the final round by landing back-to-back 1080s followed by a pair of 900s. Already an action sports icon, he returned to the U.S. a transcendent figure of American culture, immediately recognizable because of his shock of red hair and guileless charm.

Since Torino, White has solidified his position at the peak of snowboarding achievement, picking up a pair of halfpipe titles (Winter Dew Tour and Winter X Games) during the 2008-09 season. But White has hardly grown complacent with his success. He uses the handful of times he's been beaten as extra motivation to learn new tricks. And with the Vancouver Games in mind, White has quite the venue to perfect such tricks - his own private halfpipe in Colorado, accessible only by helicopter and snowmobile. White has already landed several moves, including the back-to-back double corks he debuted at the New Zealand Open in August, that have never before been executed. Expect a full arsenal of original material by 2010. White's toughest competition is likely to come from within the American ranks, with European Open champion Kevin Pearce, Steve Fisher, Mason Aguirre and 2002 and 2006 silver medalist Danny Kass among the top challengers.

Hannah Teter (left), Kelly Clark and Gretchen Bleiler finished first, fourth and second, respectively, at the 2006 Torino Games.

Friendly competitors
As with the men, the United States will field the deepest women's halfpipe team in Cypress. But unlike their male counterparts, who have devised factions and the petty feuds that follow, the women likely headlining the American effort have formed a veritable family. Consider the recent destination wedding of 2006 Olympic halfpipe silver medalist Gretchen Bleiler in Dominical, Costa Rica. A snowboarding who's who attended, including 2002 Olympic halfpipe champion Kelly Clark (who was a bridesmaid), 2006 Olympian Elena Hight, 2002 Olympian Tricia Byrnes and 17-year-old halfpipe hopeful Ellery Hollingsworth. Defending Olympic champion Hannah Teter was scheduled to join in the matrimonial merriment, but a conflicting engagement forced her to miss the event.

At 28, Bleiler is the veteran of the group and is widely considered one of the most accomplished and recognizable riders in the world. In addition to the silver medal from Torino, the darling of the sport is also a three-time X Games champion (2003, 2005, 2008). In addition to Bleiler, look for Teter to again contend for a medal. But of all the riders, none have looked as sharp as Clark. Clark has focused on the basics of her riding this past year and had her best season. With the new wave of riders coming through the ranks, she decided she couldn't rely only on superior amplitude for results. Now, she feels as confident as ever in her abilities.

Foreign attack
Despite the United States' halfpipe hegemony, there still exists a legitimate threat from abroad. On the men's side, look for Finland to upend the Americans' plans of a sweep, much as they did in 2006 when Markku Koski outperformed Aguirre for bronze. With a population just over five million (similar to that of Minnesota), the Arctic nation has managed noteworthy success in snowboarding. At the 2009 U.S. Open, Finland had three riders in the top ten, including 21-year-old Peetu Piiroinen's second place finish. Also among the talented Finnish contingent, dubbed the "Finnish Mafia" by the North American riders, is 2006 Olympian and former X Games superpipe champion Antti Autti.

As for the women, Clark has predicted "some huge upsets" in 2010. According to Clark, the potential menace could be Chinese halfpiper Liu Jiayu, who impressed in sporadic 2008-09 appearances that included a world title, a silver medal at the Olympic test event in Cypress and another silver at the New Zealand Open. Liu, 18, and a couple other talented Chinese riders will be hoping to announce their country's arrival as a snowboarding power in 2010. The American women will also face stiff competition from 22-year-old Australian Torah Bright, who lives and trains in Salt Lake City. Bright has beaten Clark for first place three times in 2009: at the X Games, Winter Dew Tour Toyota Championships and the U.S. Open. A medal for the Mormon with the striking good looks would be the first Olympic snowboarding medal for Australia.

Seth Wescott won gold in the inaugural appearance of snowboard cross on the Olympic program in Torino.

Second chances
Snowboard cross made its crashing debut at the 2006 Torino Games. Pre-event favorite Seth Wescott of the U.S. secured the event's inaugural gold in the men's competition, edging Slovakia's Radoslav Zidek at the finish. The amiable Westcott finished second in the overall 2008-09 World Cup standings and should again compete for gold in Vancouver. Teammate Nate Holland won his unprecedented fourth straight gold at the 2009 X Games and could represent a formidable challenge. On the women's side, American Lindsey Jacobellis provided one of the indelible images of the 2006 Games when she attempted a trick on the final jump, only to fall and surrender what had appeared to be an insurmountable lead. Now, Jacobellis looks to permanently put her Torino blunder behind her by upgrading to gold in Vancouver. Despite the unpredictable nature of the event, Jacobellis has been dominant, winning her fifth gold medal in six years at the 2009 X Games and the pre-Olympic test event in Cypress. Canadian Maelle Ricker is among the top international competition, but once again the event is Jacobellis' to lose.