A high-based, nighttime thunderstorm offered numerous blasts of electricity for my viewing pleasure, including this one that lit up both convective towers above and miles of cloud beneath. Obviously, the main channel of electric current here is the one through which the return stroke rushes upward, brilliantly illuminating the downward zigzag of the successful step leader. [The step leaders are invisible paths of charge which step rapidly downward from the cloud before the visible return stroke flashes up through the first one to reach ground.] But what about the downward step leaders that failed? These channels are ionized enough to glow visibly when the main one, to which they are all connected, lights up in the near-light-speed skyward surge of current from the ground. But because the step leaders point down, their channels give the illusion of a downward flash in the main channel. Very deceptive! That’s the way lightning works.
Norman OK (1 Jun 99) Looking SE
35.2325, -97.4057