How does lightning form?

So how does lightning form in a cloud? Lightning is essentially a giant spark that occurs either within a cloud or between the cloud and the ground. Lightning forms and a charge develops because of tiny collations between ice particles within the cloud.

This happens millions of times per second and as these charge particles then spread apart within the cloud larger regions of charge develop and when this charge gets large enough a lightning strike occurs.

When the lightning connects with the ground it starts off as what is called a step leader which is a channel that grows or steps from the base of the cloud towards the ground and as it steps towards the ground, when it finally connects a full channel is created and what is called the return stroke occurs which is the lightning flash that you see.