qThe dry air
is a good electrical insulator,
so a flow of current can not occur.
q For cloud-to-ground lightning to occur, a stepped-leader must emanate from the cloud base.
qThe leader is
essentially an ionized particle chamber about 10 cm (4 in) in diameter which forks repeatedly from a main channel.
qEach section
travels about 50 m in a microsecond (a millionth of a sec).
qThe sections
continue until contact is made with an unlike charged area (the ground).
q