Dangerous twisting clouds look like horizontal tornadoes

JACKSONVILLE, Fla – Look at what appears as a sideways tornado rolling above the ground. The rotating cloud is not a tornado but the dangerous rotating air generated behind planes.

The wake vortices, as they are called, can destabilize planes that follow in the same flight path. 

To avoid the hazard, aircraft typically wait a few minutes before taking off for the rotations to dissipate.

Sometimes flying planes can get jolted after hitting an old wake, just like a boat on the lake. 

Low pressure off the tips of aircraft wings produce counter-rotating vortices.

They are always present but become visible when the humidity is high. 

The quickly dropping low pressure above the wing condenses the water vapor enough to generate noticeable swirling clouds. 

This pressure drop triggers the rolling airflow downstream each wingtip with two counter-rotating cylindrical vortices.