Why does lightning prefer to strike sharp edges?
The charged pockets in clouds reach down with invisible stepped leaders (they are visible in the infrared range) to make a connection with a ground-mounted object. When they reach a certain distance above ground mounted objects, maybe 150 feet, they begin to pull charge up from below to make the connection known as lightning. Ground mounted charge is attracted to the opposite charge emanating from the clouds in the finger-like stepped leaders. The ground charge accumulates or is pulled together on edges or pointed objects making these the most likely objects to release ions or provide a streamer, which completes the connection between ground and cloud that is the visible lightning event. Several interchanges between cloud and ground may follow this same ionized path causing the flickering effect often associated with lightning strikes.
