Tom Warner of ztresearch has provided these slow-motion examples of the evolution of upward-directed, tower lightning near Rapid City, SD. Both movies illustrate flashes that were captured by a high-speed camera at an astounding 7,207 frames per second. Regarding the second movie, Tom states: "An upward lightning flash initiated from a TV tower in Rapid City, SD ... the positive polarity leader moves upward and branches into two primary channels. The right channel is weak and develops numerous recoil leaders which try to reionize the decayed branch. At one point the branch sustains growth following a recoil leader connection. The entire video is about 1/2 second."