Turbulence can be caused by many different factors, including wind, jet streams, storms, and other objects near a plane, including even another aircraft, which is known as wake turbulence and can be particularly dangerous.
In total, there are 8 different types of turbulence, which each have their own causes. These include:
- Clear Air Turbulence
- Thermal Turbulence
- Mechanical Turbulence
- Frontal Turbulence
- Mountain Wave Turbulence
- Thunderstorm Turbulence
- Wake Turbulence
The most common cause of turbulence, though, is turbulent air in the atmosphere.
What is Turbulence?
To understand what causes turbulence, it is best to first define what turbulence is.
Simply put, turbulence is a chaotic change in pressure and flow velocity.
In even simpler terms, turbulence is a sudden change in airflow.
8 Causes of Turbulence
Clear Air Turbulence
Clear Air Turbulence (CAT) suddenly occurs in clear, cloudless, weather.
It mostly occurs outside of clouds at altitudes above 15,000 feet MSL, and is caused by strong winds from the jet streams.
It can cause an aircraft to violently shake, but it’s usually not dangerous.
Thermal turbulence is caused by warm air rising from the surface or cold air moving over warmer ground.
The rising currents result in compensating slower downward currents, which leads to turbulence.
These thermal currents prevent the air from flowing normally.
Temperature Inversion Turbulence
Turbulence inversion happens when a layer of calm air rises above turbulent air.
The turbulent air brings down warm air and cools the upper part of the warm air.
The calm air on the top eventually becomes warmer, resulting in a temperature inversion.
Although temperature inversions produce a stable atmosphere, there is often turbulence between the turbulent layer and the outside atmosphere’s boundary.
Mechanical turbulence is caused by wind flow around irregular terrain or artificial obstructions, like tall buildings.
Horizontally flowing wind is disturbed by these obstructions and transformed into irregular wind movements that cause turbulence.
Frontal turbulence is either caused by rising warm air or abrupt shifts between warm and cold air.
Fast-moving cold winds cause the worst frontal turbulence.
Frontal turbulence can be especially severe if the air is moist and causes thunderstorms.
Mountain Wave Turbulence
Airflow over a mountain results in the air currents oscillating between altitudes.
This oscillation causes turbulence that extends for hundreds of miles down the mountain.
Although storm clouds are the only visible part of a thunderstorm, the turbulence caused by thunderstorms extends far outside the storms.
It’s even possible for thunderstorms to generate severe turbulence as far as 15 to 30 miles from a storm cloud.
Wake turbulence forms behind aircraft – it occurs because of atmosphere disturbances.
The most important components of wake turbulence are wingtip vortices and jetwash.
Although wake turbulence can be very dangerous, it normally only lasts for only a short duration, and smaller planes are much more greatly affected.
Is Turbulence Normal?
If you’ve flown even just a few times before, you have probably experienced turbulence at some point.
This tells you that turbulence, while it can feel uncomfortable and even scary, is completely normal and a natural part of flying.
How Long Can Turbulence Last?
There’s no doubt that when you experience turbulence at 35,000 feet, it can be a very scary experience.
Because of this, turbulence can seem like it lasts for an eternity, even when it only lasts for a few minutes.
In actuality, turbulence lasts between 10 and 15 minutes on average.
Is Turbulence Dangerous?
When considering if turbulence is dangerous or not, we need to know how turbulence is classified.
- Light Turbulence: Light turbulence features slight changes in altitude with minor effects on a plane and its passengers.
- Moderate Turbulence: Moderate turbulence features changes in altitude, and the effects are felt more intensely. However, the aircraft remains in positive control at all times.
- Severe Turbulence: Severe turbulence involves large, abrupt changes in altitude and/or attitude. A pilot may momentarily lose control of the aircraft.
- Extreme Turbulence: Extreme turbulence results in an aircraft being violently tossed out. Even the most experienced pilots will find it practically impossible to control the aircraft. The aircraft may experience structural damage.
Can Turbulence Cause a Plane to Crash?
To put your mind at ease, it is exceptionally rare for turbulence to crash a plane, especially if we’re talking about commercial airliners that we all travel on.
This is because planes are engineered to withstand even the most severe turbulence – 1.5x force on their airframes, in fact.
However, a notable plane crash due to turbulence was American Airlines Flight 587, which crashed in New York in 2001.
The crash was more to do with pilot error, though.
The first officer overused the rudder controls in response to wake turbulence from a preceding aircraft that took off minutes before.
Do Pilots Know When Turbulence is Going to Happen?
Pilots rarely head straight into turbulence without any warning.
Pilots are aided by a range of technologies and information to inform them of upcoming turbulence, including pre-flight weather reports, onboard weather radar, and reports from others planes.
The Most Turbulent Flight Routes
You can expect to experience the most turbulence on the following routes:
- New York to London
- Seoul to Dallas
- London to Singapore
- London to South Africa
- Flights during monsoon season in South Asia
- Flights into Denver