Formation - Heating of the ground and rising air, warm air rises and atmosphere becomes unstable, cumulonimbus clouds, wind shear occurs (lower wind speed on the lower parts of the storm, higher wind speed on the higher part of the storm), rolls over the slower air, creates a cylinder, updrafts cause the cylinder to tilt vertically.
Cylinder updraughts take place in storms called supercells, down drafts of cold air bring the column downwards to the ground, this forms a tornado.