Lightning belongs to the
group of meteors other than clouds, the so-called electrometeors.
Lightning is the flash of light
accompanying a sudden electrical discharge which takes place from or
inside a cloud, or less often from high structures, the ground or
mountains. Lightning is caused when the negative charge in the lower part
of the cloud and the positive charge in the upper part of the cloud become
so great the air within the cloud breaks down to allow an electrical
current to flow through it and discharge. The mechanism of charge
separation is still highly debated. In my area thunderstorms usually occur
20 to 30 times a year.