Hockey had little to do with it, although I heard one person suggest that the violence in the game of hockey may have had some impact.
The official story is that a small group of anarchists came equipped with tools to break windows and bottles of flammable liquid to set the fires. The fires did seem to start rather easily and quickly at the end of the game. However, then there were the thousands of well-lubricated fans who encouraged the hooligans or joined in and many thousands more who stayed to watch and shoot pictures and video with their phones and cameras.
Thousands of photos and video have been posted on Facebook and the like. Face-recognition software is available to enable the police to 'tag' and identify many of the idiots who participated.
If you go to: http://www.npr.org/blogs/pictureshow...ot?sc=fb&cc=fp
you will see probably the iconic photo from the riot. Some are suggesting the picture was a set-up, but I know the photographer, Richard Lam and I have covered my share of riots, and believe me, you're only concerned with your own safety and with getting the picture.
Best comment on the picture was "at least somebody from Vancouver can score on the road".