YouTube user Andrew92106 explains what went wrong:
The Big Bay Boom Firework Show in San Diego for 2012 was a “Big Bay Bust”. There was a technical problem and ALL of the fireworks went off within 30 seconds. The original Big Bay Boom was set to last about 15 minutes.
And it all went down about 5 minutes before the show was slated to start.
Well, at least it was nice while it lasted.
Have a look: