Cloud-to-ground lightning: A “stepped leader,” which is invisible to the naked eye, will zigzag downward in roughly 50-yard segments in a forked pattern. A return stroke of bright luminosity travels about 60,000 miles per second back toward the cloud. A flash consists of one or perhaps as many as 20 return strokes.

Cloud-to-air lightning: Cloud flashes sometimes have visible channels that extend out into the air around a storm but do not strike the ground.

Intra-cloud lightning: Lightning that is embedded within a cloud that lights up as a sheet of luminosity during the flash.

Cloud-to-cloud lightning: Lightning that strikes from one cloud to another and doesn’t reach the ground