A positive cloud-to-ground lightning flash triggers upward positive lightning leaders to form from three television towers in Rapid City, South Dakota. Filmed at 9,000 images per second, the video shows positive leaders descending from the thunderstorm with one connecting to ground. The resulting return stroke creates a fast electric field change which causes three tall television towers to initiate upward positive lightning leaders. Fast, short duration, bidirectional/bipolar recoil leaders form on positive leader branches that become cutoff from their main channel.

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