They can be either resulting from direct strikes or induction into power or signal cables, or induced, either through capacitive or inductive coupling. Within the cloud formation, strong updrafts and downdrafts generate high electrical charges. When the voltage reaches a sufficiently high level both cloud to cloud and ground discharges occur. Strikes occur when the ground is at positive polarity and the cloud negative region attempts to equalize with ground. Alternatively strikes can occur when the positively charged cloud top equalizes with the negative ground, or when the positive charged ground equalizes with the negative charge cloud or the negatively charged ground equalizes with the positive charged cloud top.
Lightning consists of a number of components, which form a multidirectional flow of charges.
The positively charged ions rise to the cloud top, and the negative ions migrate to the cloud base. Regions of positive charged ions also form at the cloud base. Eventually the cloud charge levels have sufficient potential difference between ground and another cloud to discharge. The leader consists is a negative stream of electrons consisting of many small forks or fingers that follow and break down the air paths offering the least resistance. The charge follows the fork finding the easiest path as each successive layer is broken down and charged to the same polarity as the cloud charge.