A small one starting to form in its early stages as a cumulus cloud.
This cumulus cloud is already 12 kilometers high and filled with rain, hail and snow at the upper levels.
The beautiful white billows as seen from above.
These are created by updrafts of rising air. The air rises because as the water vapor condenses to form rain droplets it releases latent heat. The warmer air rises and causes more water vapor to condense as it cools, releasing more energy.
This cause it to rise even faster and this process continues as long as there is moisture in the air to release energy as it condenses.