My understanding is that the bolts you see approaching each other are precursors. When they touch, the circuit is completed and the current starts flowing, crea

My understanding is that the bolts you see approaching each other are precursors. When they touch, the circuit is completed and the current starts flowing, creating the bright flash we associate with lightning. That saturates the camera's sensor. The left-over bolts are just extremely hot air left in the path of the discharge.