Development of a Lightning Strike

August 10, 2014

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Photographer: Greg Parker
Summary Authors: Greg Parker; Jim Foster
 
The photo sequence above shows the development of a lightning strike over southern England, on the night of July 18, 2014. This particular cloud-to-ground bolt looks like the classic lightning bolt used to alert people of the danger of an approaching storm. It may seem like exposure 3 (out of 10) is out of sequence, but in fact this is the return stroke -- returning from the ground to the cloud. If lightning is observed to flicker, there's more than one return stroke. Following the initial stroke, when the lightning channel has been cleared of charged electrons, other electrons outside this channel may enter it, initiating another stroke. This can occur multiple times over a fraction of a second making the bolt appear too flicker.