Turbulence is chaotic, irregular movement in a fluid, whether that fluid is air, water, or anything else that flows. In everyday conversation, it almost always refers to the bumpy, jarring motion you feel on an airplane when the air around it becomes unstable. But in physics, turbulence describes something more fundamental: the point at which smooth, predictable flow breaks down into a swirling, ever-changing pattern of motion happening at many different scales simultaneously.
Turbulence in Physics
All fluids, including air and water, can flow in two basic ways. Smooth, orderly flow is called laminar. Turbulent flow is the opposite: chaotic, unpredictable, and full of fluctuations in speed and pressure. When a fluid moves fast enough or encounters enough disruption, it transitions from laminar to turbulent. You can see this happen when you turn a faucet from a trickle to full blast. The stream goes from glassy smooth to a sputtering, splashing mess.
What makes turbulence so difficult to study is that it involves motion at many scales at once. Large swirls of fluid break into smaller ones, which break into even smaller ones, all the way down to tiny eddies where the energy finally dissipates as heat. Researchers at UC San Diego have shown that even the friction a turbulent fluid creates against the walls of a pipe is directly connected to these small-scale speed fluctuations. Turbulence remains one of the most complex unsolved problems in classical physics.
What Causes Turbulence on a Flight
When pilots and meteorologists talk about turbulence, they’re describing pockets or regions of unstable air that jostle an aircraft. Several distinct mechanisms create it.
Clear-air turbulence is the type that catches passengers off guard because it happens in cloudless skies with no visible warning. It’s caused by sharp differences in wind speed or direction at different altitudes, known as wind shear. It typically occurs above 15,000 feet, often near the jet stream, and is most common in winter. A patch of clear-air turbulence can stretch 50 miles long, 20 miles wide, and about 2,000 feet deep.
Convective turbulence comes from uneven heating of the Earth’s surface. On a warm day, dark pavement and rocky ground absorb heat faster than grass or water, creating columns of rising warm air and sinking cool air. Flying through these invisible currents produces the familiar bumps you feel on summer afternoons, especially during takeoff and landing. Sometimes these currents build into thunderstorms, which generate far more intense turbulence.
Mountain wave turbulence forms when strong winds (25 knots or more) blow roughly perpendicular to a mountain ridge. The air flows over the peaks like water over rocks in a stream, creating rolling waves and eddies on the downwind side. The most intense mountain wave turbulence occurs when the atmosphere on the downwind side is stable, which traps the energy of those waves rather than letting them dissipate.
Mechanical turbulence near the ground is caused by wind flowing around obstructions like buildings, hangars, and uneven terrain. These obstacles break the airflow into gusts and eddies that can carry downstream for a surprising distance. Large aircraft also leave powerful spinning vortices behind their wingtips, which is why smaller planes must wait before taking off or landing behind a bigger jet.
How Intensity Is Classified
Aviation authorities classify turbulence into light, moderate, and severe categories based on how much the air’s energy fluctuates. Light turbulence causes slight, rhythmic bumps. You might notice your coffee rippling. Moderate turbulence makes unsecured objects shift around and walking through the cabin becomes difficult. Severe turbulence can momentarily throw unbuckled passengers out of their seats, and the aircraft may experience brief, abrupt altitude changes.
Pilots report turbulence intensity in real time using a standardized measurement called eddy dissipation rate, which quantifies how much energy the turbulent air contains. These reports feed into weather systems that help other pilots on nearby routes know what to expect.
Can Turbulence Damage an Airplane?
Modern commercial aircraft are engineered to handle forces far beyond what even severe turbulence produces. Wings are designed to flex, not snap. In certification testing, they must withstand loads up to 2.5 times the force of gravity in an upward direction and negative 1.0g pushing downward. Engineers use a technique called aeroelastic tailoring, which exploits the directional stiffness of composite materials so the wing bends in a way that actually reduces the stress from gusts.
The real risk from turbulence isn’t structural failure. It’s injury to people inside the cabin. According to FAA data compiled from NTSB reports, there were 20 serious turbulence injuries on U.S. commercial flights in 2023: 3 passengers and 17 crew members. “Serious” in this context means injuries requiring hospitalization for more than 48 hours, bone fractures, or damage to internal organs. Flight attendants are injured at far higher rates because they spend much of the flight standing and moving through the cabin. For passengers, the single most effective protection is wearing a seatbelt whenever you’re seated.
Where to Sit for a Smoother Ride
If turbulence bothers you, choose a seat over or near the wings. Think of the plane like a seesaw: the people at each end experience the most vertical movement, while someone sitting at the pivot point barely moves. The wings are located at the aircraft’s center of gravity, so seats in that section experience less pitching and bouncing than seats in the front or, especially, the back of the plane. You’ll still feel the turbulence, but the intensity is noticeably reduced.
Turbulence Is Getting More Common
Clear-air turbulence over the North Atlantic has increased significantly since the late 1970s, and climate change is the primary driver. A study published in Geophysical Research Letters analyzed four decades of atmospheric data and found that severe clear-air turbulence became 55% more frequent between 1979 and 2020. Moderate-or-greater turbulence rose by 37% over the same period. Even light turbulence increased by 17%, adding roughly 80 more hours per year at a typical point over the North Atlantic.
The mechanism is straightforward: a warming climate strengthens the jet stream’s wind shear, particularly at cruising altitude. Climate models project that if atmospheric carbon dioxide doubles from pre-industrial levels, moderate-or-greater clear-air turbulence could increase by around 84% over the North Atlantic. That doesn’t mean flying becomes dangerous, but it does mean bumpy flights will likely become a more routine part of air travel in the decades ahead.
How Pilots Detect and Avoid It
Turbulence associated with storms shows up on onboard weather radar, which detects moisture in the air. Clear-air turbulence is harder to spot because, by definition, there’s nothing visible for radar to bounce off. Pilots rely on a combination of pilot reports from other aircraft, weather forecasts highlighting areas of strong wind shear, and real-time turbulence data shared through automated systems.
NASA has been developing laser-based detection systems (called Doppler lidar) since the late 1970s that can measure wind speeds ahead of an aircraft by bouncing light off tiny particles in the atmosphere. Early airborne tests successfully detected mountain wave turbulence and other clear-air hazards before the aircraft reached them. These systems work by measuring how the frequency of reflected light shifts based on the speed and direction of air movement, giving pilots advance warning of what lies ahead.