Lightning Stroke
¥Cloud-Ground Sequence
¥1) Downward stepped leader. Stepped leader is invisible.
¥2) Upward return stroke.
¥3) Downward dart leaders.
¥4) Upward return strokes.
¥Dart leaders-return strokes: up to 25 cycles, 3-4 usually.
¥Ground strikes are usually negative, that is electrons flow from cloud to ground.
Williams, The Weather Book