Excellent slideshow.
Shockwaves in high humidity conditions become visible around bomb blasts too.
Or Cannon shots , where they often form rings.
And at the intakes of stationary jet engines where the vortexe somtimes look like writhing pythons.
I would like to fire this thing in a fog.
http://www.youtube.com/watch?v=X2fVjBd0xo4&feature=related