What You Didn't Know About Turbulence

Turbulence has been in the news lately, from the story of seven people being hurt on a flight from Texas to Germany that had to land after significant turbulence to the 36 people injured on a flight to Hawaii. To get a better understanding of turbulence, I talked with Dr. Todd Lane, a professor of Atmospheric Science at Australia's University of Melbourne. Here’s our conversation.

What causes air turbulence?

Turbulence in the atmosphere occurs when the air flow shifts from moving mostly horizontally, called laminar flow, to moving vertically. The vertical air movements are what causes the turbulent (i.e., bumpy) response from aircraft when they pass through a patch of turbulence.

W​hat are the different types of turbulence?

There are three main sources: 1) thunderstorms, which cause turbulence within and around storms; 2) wind shear, i.e., strong changes in wind speed with height, can cause turbulence, which is referred to as Clear Air Turbulence (CAT) and often occurs in jet streams; and 3) air flow above and around mountains can cause turbulence.

Pilots sometimes say they're heading to different cruising altitudes to attempt to avoid turbulence. How effective, generally, is this?

This is a very effective way of avoiding turbulence. Turbulence in the atmosphere typically occurs in shallow, pancake shaped layers that may only be a few hundred meters in the vertical dimension. Thus, moving upward or downward can effectively move out of these layers and avoid the turbulence.

Short answer is “yes”; the reasons and explanations are more complex and also related to flight routes. In some regions of the world, storms are expected to become stronger, and it would be reasonable to assume that the turbulence caused by these storms might be more intense and widespread.

Turbulence from jet streams, called “Clear Air Turbulence” (CAT), should change as well. In some regions, climate change should cause the jet streams to intensify, which will create more turbulence. Climate change also causes the jet streams to shift into common flight routes, making those routes potentially more susceptible to turbulence.

I​s air turbulence dangerous?

Yes, passengers and crew can be seriously injured by turbulence encounters. The risk is alleviated if passengers and crew are seated with their belts on, but it is the surprise encounters that pose a significant risk to health and safety.

Have scientists learned anything new about air turbulence over the past decade or so?

Perhaps the biggest advances in our understanding of turbulence are related to how thunderstorms generate turbulence. We’ve been able to show that storms can sometimes generate turbulence more than 100 km away, creating a distant turbulence risk in addition to the well-known turbulence within storms.

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.