As most other replies have pointed out, it's definitely a light leak. Seeing as 16mm film is getting increasingly more popular in the snowboard film industry (if you can call it that), then it only makes sense that some of this movie was shot with a combination of 16mm film and digital HD video.
Another perfect example of such heavy use of 16mm film in a snowboarding movie would be "Montreal: a 16mm Snowboard Documentary" which was entirely filmed with a 16mm film camera. And it's also got an incredible mix of scenery (street and mountain) and music.
Actually, here's a video that one of the main filmers shot in a helicopter circa 2006. Looks like "That's it, that's all" wasn't completely revolutionary in their soundtrack choice after all.