A380 Wake Turbulence

Most people are unaware that airplanes make waves in the air much like boats make waves in the water.

The shape of an aircraft's wing causes the area above the wing to have lower air pressure then the area below the wing. This generates lift, but also creates an undesired side affect.

At the tips of the wings, higher pressure air swirls up, around the wingtip and into the lower pressure area on top of the wing. This creates a sort of a sideways tornado known as wingtip vorticies.

This video provides a visulization of this very dangerous type of turbulence. LINK, Via: Youtube