Simply speaking, turbulence is a disturbance of the regular flow of air. Many people can more visualize turbulence in water as an eddy in a river or waves in the ocean. “It helps to visualize flight as a river flowing rapidly over rocks, where water is forced upward and then down, with swirls and eddies,” says Captain Chesley “Sully” Sullenberger, retired US Airways pilot, speaker, author and CBS news safety & aviation expert. In short, turbulence is a normal part of flying and every pilot knows that they might encounter it in the course of a given flight. Air in the atmosphere can move up and down or sideways. The wings of the aircraft are engineered to resist and adjust to these movements. Turbulence is everywhere in the atmosphere just like movements are in bodies of water. It’s normal and how the sky behaves naturally. In fact, the twinkling we see in stars of the night sky is really evidence of moving air in our atmosphere not pulses of energy from distant suns.
There are different types of turbulence each with their own characteristics. Clear air turbulence is cause by variations in the Jet Stream. There’s more in the winter and when the jet stream brings cool air south, it crosses common flight paths across the Pacific. We’ve all seen the jet stream dip on the Weather Channel. Convective turbulence ramps up more in the summer when thunderstorms occur commonly in air traffic areas. Low level turbulence can result from ground topography, daily weather and even tall buildings. A more distinct type has its own name: mountain wave turbulence which if you are from Denver you are very familiar with. And, finally there’s wake vortex turbulence which comes from lift even a strong as a tornado. Turbulence can be light or stronger just like water in a stream. If you think you have experienced major turbulence it’s likely the pilot would call it moderate.
Pilots generally have a good idea where the flight will encounter turbulence but not always. They can reference different systems that track turbulence, observe weather reports and even get reports relayed by other pilots that are flying in the same area. Pilots want you to have a smooth and enjoyable flight so they make great effort to dodge areas of turbulence by changing altitude or circumventing a disturbance. But, sometimes there’s simply nothing they can do. They will have to ride it like a surfer and hopefully navigate out as soon as possible.