The twirl is interesting I seen other photos of aircraft popping flares with that twirl.It would require perfect timing for the photographer to catch that happening most likely the camera also has just the right aperture settings.
The aircraft also would have to be at the correct angle of attack so that the prop or jet wash caused the flare to twirl not something you usually want to occur except for show.
The timing and number of flares dumped can be changed to make a cool pattern for an air show normally those are the kinds of flare photos that you will see.
The photo was taken at an exercise not an air show seems that the Transall got a sudden IR hit and had to pop flares and pull hard to try and evade the lock.
http://www.aviationweek.com/Blogs.as...0-c255dbd41f21