Seattle Sounders - Fans - Boom, Boom, Clap

Seattle and Toronto are almost at opposite ends of the continent. And yet, when Toronto FC and the Seattle Sounders host Leg 2 of their respective Conference Championships this week, at least one element of the atmosphere at BMO Field and CenturyLink Field will sound the same.

Both teams' supporters are among the league's most well-known users of the Viking thunder clap, or the "Icelandic Clap," as it became known after Iceland's deeper-than-expected run in the 2016 UEFA European Championship.

The instantly recognizable cheer is simple and catchy: A single clap from arms raised above the head in a V shape, punctuated with a simultaneous guttural grunt, increasing in tempo and intensity until becoming thunderous applause. In some versions, like in this video of the Iceland national team's triumphant return to their homeland, it starts with two drumbeats signaling the clap, reminiscent of Queen’s seminal stadium-stomper “We Will Rock You.”

But while informal soccer historians point to conflicting origin stories that attribute it to Scottish club Motherwell, French club Lens, or the shield-banging, CGI-enhanced Spartans of the 300 film franchise, the home supporters in both second legs have been using it for years.

Toronto have long utilized it as an in-game show of support. And perhaps most famously, Seattle supporters deploy it to welcome players on the pitch as one of the league’s most iconic pre-game ceremonies. And yes, even after Iceland made it internationally famous, both teams’ fans will keep to their traditions.

Though two current TFC supporters’ group leaders offer conflicting stories of how they adopted it, they both agree that the Toronto version of the clap started some time in the 2008 season. Mike Langevin with Red Patch Boys attributes it to the now-defunct North End Elite, while U-Sector’s Tobias Vaughn remembers one of the original U-Sector capos (perhaps drawing on Croatian heritage) introducing it to the TFC faithful. While both supporters’ groups in the South End have maintained over the years, the Euros have recently helped inspire fans in other sections of the stadium join in.

Hear that at the beginning of Leg 2? It's the Viking thunder clap -

The Sounders also enjoy a long history with what they call the “boom boom clap,” or BBC for short. Paul Cox, former president of the Alliance Council (an organization serving as a liaison between Sounders season ticket holders and the front office), recalls that Emerald City Supporters experimented with BBC throughout their inaugural MLS season in 2009. They soon seized upon the pre-game procession, when players emerged from the Qwest Field (now CenturyLink Field) tunnel onto the pitch, as an ideal moment to launch into the “boom boom clap.”

According to Cox, it took a while to get the balance right between the fan-led BBC and the official “MLS Processional Anthem” that teams play.

“The stadium game production crew initially tried to work against it, turning up the volume on the intro music,” Cox remembers, “but after a couple of games, as BBC took hold, they realized it was better (for the crowd overall) than [just] the intro music.” 

Hear that at the beginning of Leg 2? It's the Viking thunder clap -

Today, it works well. “They keep the volume balanced with the BBC, so they're not trying to overwhelm it; they just let the anthem fill in, rather than being the dominant thing,” Cox says. “It's a good example of how the club has learned to let the fan-driven stuff take the lead.”

The tradition established by Sounders fans has also carried over to USMNT supporters the American Outlaws, who have in turn adopted “boom boom clap” as a go-to cheer. According to AO’s Donald Wine II, the 2013 Hex match in Seattle, in which the US defeated Panama before a gloriously loud and decidedly pro-American crowd, helped popularize the cheer for AO faithful.

 “It's visual. It's simple. It's not a quick chant -- it's just clapping on cue -- so it's able to flow out and get everyone involved,” he says. “We've done it at stadiums where, by the time it's done, the entire stadium is doing it with us. That's what makes it great.

“No one needs to memorize lyrics to do it,” he adds. “It's something I hope we continue doing in the style that we've been doing all these years. It can unite supporters and casual fans and really help create a unified home atmosphere where everyone is together supporting as one.”

Listen for them both in both of the 2017 Audi MLS Cup Playoffs matches this week. Toronto FC host Columbus Crew SC on Wed., Nov. 29 at 7:30 pm ET (FS1 in US, TSN and TVAS in Canada), and the Seattle Sounders host the Houston Dynamo on Thurs., Nov. 30 at 10:30 pm ET (ESPN and ESPN Deportes in US, TSN and TVAS in Canada).