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The above animation has been made of the frames of a Hi-8 video recording. The time between the frames is 1/25th of a second. The lightning strike is one of the series produced by a thunderstorm on May 29th 1999, Wageningen, The Netherlands. It does not strike the flat but somewhere (maybe an antenna) in the hills.

You can nicely follow the process of the lightning discharge: from the lower thunderstorm region, which is negatively charged, a stepped leader descends to earth. The stepped leader could be captured on video because the cloud base is relatively high (about 2 km, or 6000 ft), so that it takes longer for the leader to reach ground. Just before the stepped leader reaches the ground (not seen here), a streamer shoots upward towards the stepped leader.
Upon contact, a wave front (return stroke) travels above along the channel, draining the electrons to the earth. This is the bright flash we see. The branches of the channel also subsequently get discharged, first the lower, then the higher branches. The return stroke process occurs too fast for the camcorder, as it goes at 1/3 of the speed of light.

After this return stroke the channel cools in this case. The brightness of the ionised air in the channel decreases. In some curves this happens less fast, a bit reminding of bead lightning. Sometimes more discharges can take place along the channel. The a dart leader comes down, lightening up the channel again. This is the flickering we often see.

There is yet another thing to see: very short before the return stroke takes place, a second leader comes down to the left of the first lightning, but does not reach earth. Apparently the return stroke broke down the built-up electric field, so that the second leader could not propagate towards the ground anymore.

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