Lightning has a very high peak voltage and current, and progresses down/up as the voltage ramps up, at this time there is little current, as the 'leader' follows the gradient. At this time there is a charged conductor in the thunder head.
when the leader finds a low conductivity path to the earth the leader draws current and discharges the stored charge, usually in many short discharges very close together in time.
This is a very fast discharge, with a very high voltage peak = induction aspects can influence the path. After a full plasma has established = a short to ground = large charge transfer. This charge transfer usually reduces the voltage = spark stops, but a path is still there and more charge follows. youtube has a number about lightning leaders/streamers https://www.youtube.com/results?search_query=lightning+leade...
Buildings usually have a high point array of many sharp spikes and top and edges that can suppress lightning by feeding a shorting current to the charge. Often a strike does not occur, but often it does. Many high building are struck hundreds of times in a storm. Usually the steel frame shorts these to ground, but peaks are so high that a bolt can jump to a close item, like a tree, because the current is so high the voltage drop can make a sub-leader arise. This is a greater risk with trees and a travelling bolt can choose a local salt water conductor = you under a tree - which is why you do not stand up in row boats or shelter under trees. Look for low ground, lie down and hope that guy on a golf cart, under a tree, is the Darwin Award winner...