You've seen lightning countless times before, but have you ever actually seen the birth of a lightning bolt? Three years ago, electrical engineers Joan Montanyà and Oscar van der Velde of the Polytechnic University of Catalunya in Barcelona, Spain set up a high-speed camera in the Ebro Valley of northeastern Spain amidst a tremendous lightning storm, and filmed the luminous carnage above in super-slow motion. Among the flurry of cloud-covered flashes and ground strikes, the duo was lucky enough to catch a rare sight on camera: a lightning bolt entirely outside of a cloud.

They revealed their footage, along with an in-depth description, last Friday in Nature's Scientific Reports.

The clip above is thirty-two seconds long, but the events it depicts lasted roughly 25 milliseconds in reality. The two squiggly white lines you see at the beginning are both charged lightning channels extending out from the clouds above. At around one second (0.09ms), a path of ionized air called a leader forms at the end of the lightning channel at the right. As it branches and extends out, it eventually comes into contact with the charged channel on the left at roughly seven seconds (6.1ms). At this point, the electrical resistance in the air breaks down and a flash of electrical energy occurs between the two channels: a lightning bolt.

While we thank Montanyà and van der Velde for the electrifying and elucidating footage, we remind them that lightning storms can be quite hazardous, and next time, it might be wiser to seek shelter.

Source: Montanyà, J. et al. The start of lightning: Evidence of bidirectional lightning initiation. Sci. Rep. 5, 15180; doi: 10.1038/srep15180 (2015).