Clear-Air Turbulence Explained

Turbulence does not require a thunderstorm. At cruise altitude, layers of air moving at different speeds or directions can become unstable and create rough air in otherwise clear skies. Because ordinary weather radar detects precipitation rather than invisible wind shear, clear-air turbulence can be harder to see in advance.

Wind shear aloft creates unstable layers

When adjacent air masses move at different speeds, waves and eddies can develop. Jet-stream boundaries are common regions for these sharp gradients.

Weather radar may show nothing

Conventional onboard radar highlights precipitation, not dry turbulence. A clear radar screen therefore does not guarantee a smooth ride.

Forecasts identify areas of elevated risk

Meteorological models estimate turbulence using wind, temperature and atmospheric stability. Dispatchers and crews use those products when selecting routes and altitudes.

Pilot reports provide immediate local information

Aircraft ahead may report the altitude and intensity of turbulence. Controllers can pass those reports to following flights, which may request a different level.

Changing altitude can improve the ride

Turbulent layers may be relatively shallow. Climbing or descending a few thousand feet can move the aircraft into smoother air if traffic and performance allow.

Seat belts are the simplest protection

The aircraft is designed for substantial turbulence loads, while unrestrained occupants are more vulnerable to injury. Keeping the belt fastened when seated reduces that risk even when the sign is off.

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