4-Steps of Lightning

Step 2: The Stepped Leader signals a building of charge within a cloud. There may well be many attempts of Stepped Leaders to seek a good contact with a ground object and the sky may be filled with these splintered fork-like flashes for some time, and a crackling sound. These flashes are attempts to discharge the clouds electrical intensities. They also induce in the underlying ground a build-up of opposite (+Charge) electrical energy. When sufficient charge has built up and the Leader approaching ever closer to a ground object, a contact is made and a massive discharge occurs.