Cloud-to-cloud lightning refers to lightning discharges occurring between cloud areas without contacting the ground. It can be further divided into inter- and intra-cloud lightning; the former referring to lightning between two separate clouds and the latter to lightning within a single cloud. Intra-cloud lightning – also called in-cloud lightning – is more common than inter-cloud lightning as single clouds can be huge with areas of differing electric potential.

This photo was taken from Montrose Harbor looking South toward the city.