Bumpy flight: Clouds and air traffic
Sure, there is turbulence of clean air. But when your plane ride becomes bumpy, you will probably look out the window and see the clouds. They can range from inflated cumulus clouds, alias nice weather clouds, monstrous cumulonimbus with their characteristic anvilized peaks, undulating sides and ominously dark bases. The fact is … the clouds are colder than the surrounding air. So it is contrast in the density between the clouds and the surrounding air, which creates a kind of “hole” in the sky, which makes the ride less smooth.
Weather and aircraft performance
Mike Sueflohn has been a private and commercial pilot for over 23 years. As a pilot, he must attend recurrent training to discuss how the weather relates to aircraft performance. Some of the issues they focus on are takeoffs, landings and concerns, such as wind shear. Sueflohn said EarthSky:
Much of the weather, including the turbulence we have in flying, is derived from the sun and the uneven warming of the earth’s surface. As a result, you may experience turbulence at any time. Usually early in the morning and later in the evening and all night you can find the best time for smooth rides.
Most commercial airlines fly a large part of the clouds, although they still have to fly through them to get to and from airports. A typical commercial jet has a cruising altitude of about six to seven miles (nine to 11 km) above sea level. So in long-haul flight, the plane will generally be above most of the clouds except the cirrus and towering cumulonimbus.

Cumulonimbus: A natural bypass sign for aircraft can cause bumpy flights
As you can guess, storm clouds – specifically cumulonimbus – are the types of clouds that pilots want to avoid the most. Cumulonimbus clouds generally contain heavy rain, lightning, hail, strong wind and occasional tornadoes. Pilots and air traffic control pay close attention to the weather and flights on the route around these types of storms. As Sueflohn said:
We respect and pay attention to the frontal boundaries, where there is the potential for storm activity / energy. The clouds commonly associated with these boundaries that we are dealing with are cumulonimbus. It would be a good idea to consider alternative flight planning options if these conditions exist.
Mammatus clouds
Another type of cloud associated with cumulonimbus is mammatus. Mammatus are bubbling pockets of air that hang under the base of the cloud. Web page TheAirlinePilots he said:
Airline pilots usually take steps to avoid any cumulonimbus clouds, but especially those carrying mammatus formations, as these indicate extremely strong turbulence within cumulonimbus. Mammatus can be observed wherever cumulonimbusus occurs, but it is especially common in areas where there are severe storms, such as tropical and subtropical areas. Due to the fact that the formation is associated with mature cumulonimbus clouds, it is most likely to be seen from afternoon to early evening, when the warming of the earth and the associated convection activity have reached its maximum.
You can find out more about why pilots avoid cumulonimbus clouds in the video below.
Other types of clouds
All clouds are formed by water droplets or ice crystals. Clouds are coming in wide selection various types, from thin to thick and inflated and ranging from low to ground to top troposphere (and sometimes in stratosphere. There is even one type of cloud, called the noctilucent cloud, that exists in mesosphere). That’s what air traffic control specialist Jeffrey Hormann said EarthSky how some of the different types of clouds can affect aircraft:
Cumulonimbus poses the greatest danger due to turbulence along with all standard storm tariffs. The cumulus clouds themselves represent the probability of turbulence in the rising currents below them, but above them is smooth air. Stratus they often contain icy icing, especially at their peaks, during colder periods. Fog and lower visibility limit aircraft to approaching airports at which, under minimum conditions (visibility 1/2 mile and a cloud base of 200 feet are normal), aircraft cannot continue landing.

Read more about some unusual cloud types:
Punching clouds are produced by nozzles
Undulatus clouds look like wavy lines
The Kelvin-Helmholtz clouds look like ocean waves
Cloud gallery of aircraft



Bottom line: Many types of clouds and even clear skies can cause bumpy flight in an airplane. But cumulonimbos are the most important clouds that planes avoid.
Kelly Kizer Whitt
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About the author:
Kelly Kizer Whitt has been a science writer specializing in astronomy for more than two decades. She began her career in Astronomy Magazine and, among other things, regularly contributed to AstronomyToday and the Sierra Club. Her picture book for children, The Solar System Forecast, was published in 2012. She also wrote a dystopian novel for young adults called A Different Sky. When not reading or writing about astronomy and looking at the stars, she enjoys traveling to national parks, crossword puzzles, running, playing tennis, and paddleboarding. Kelly lives with her family in Wisconsin.