Illustration showing the formation of a tornado. A wind shear forms; surface winds roll air into a horizontal tube. Sun warmed air lifts a section of the vortex vertically creating an updraft. A storm forms; one side of the vortex becomes stronger and forms into a thunderstorm, while the other side dies. A supercell is formed when a mesocyclone pulls more warm air up into the storm, allowing it to grow. The rotation can be enhanced by the interaction of cold and warm air currents (red and blue arrows).The spin then intensifies and a rotating column of air will break through the wall cloud and hit the ground.