Pourquoi le vol dans un nuage est-il si turbulent ?

https://www.boldmethod.com/learn-to-fly/weather/why-theres-usually-turbulence-inside-clouds-in-flight/

You’re flying toward a puffy cumulus cloud and out of habit, your natural instinct is to tighten your seatbelt. It may seem like a simple question, but have you ever wondered why clouds can be so bumpy?