In an email from the photographer who took the picture, Wayne Pryde, Wayne said:
I had taken 38 shots at 15 second intervals at a shutter speed of 1/20 and aperture of 5.6. I can confirm that there were definitely no fireworks happing on that evening.
As stated in the APOD, I am not sure what caused the streak and flash. My hope is that this discussion will zoom in on the correct answer or narrow the realistic possibilities.