There are 5 main types of turbulence: convective, clean air, mechanical, wake, and chaotic turbulence. Convective turbulence occurs when warm air rises from heated ground and passes other air masses. Clean air turbulence happens when planes cross between air masses moving in different directions, such as jet streams. Mechanical turbulence is generated when a solid object obstructs airflow, like a rock in a river. Wake turbulence is caused by planes disrupting air as they pass through it. Turbulence in general can be defined as chaotic and unpredictable airflow.