What is defined as turbulence occurring in the absence of clouds?

The phenomenon described as turbulence occurring in the absence of clouds is known as Clear Air Turbulence (CAT). This type of turbulence typically occurs at high altitudes, often in clear air, away from storm systems, and is frequently associated with jet streams or variations in wind speed.

CAT can be unpredictable since it does not present the visual cues, such as clouds, that pilots often rely on to anticipate turbulence. It can occur during strong temperature inversions or when air masses with different characteristics interact, contributing to its occurrence in seemingly calm air.

Understanding Clear Air Turbulence is crucial for pilots and dispatchers alike, as it poses challenges for flight planning and passenger comfort due to its sudden nature and inability to be detected visually or by radar.