It's fairly simple. In DaVinci Resolve, I overlayed white clips of random length (not more than 1 or 2 frames at a time), with different opacity depending on how long and how bright I wanted the lightning burst to be. (Set 'Composite Mode' = Overlay).
For the actual lightning strike, almost the...
I am a science-fiction writer, recently got interested in writing & directing zero budget short films. I made two shorts so far, 'Myriad' and 'The Boogeyman'. I am also into cinematography and editing. Obviously, my two shorts are a one man show :) And here is my latest, 'The Boogeyman'.