China: Ethereal 'rainbow cloud' enchants Haikou residents; Know what caused the phenomenon

Residents in China's Haikou were enthralled to see a rainbow in the sky that resembled a cloud. However, the phenomenon was not a rainbow at all, but rather an actual cloud.

On August 21, a pileus cloud, also known as a cap cloud and a scarf cloud, was visible in Haikou. A pileus forms when the rapidly rising air in a cumulonimbus updraft, also referred to as a cumulus cloud, pushes against the cooler air above it. As a result, moisture condenses directly along the top of the updraft, leading to the formation of the pileus.

What caused the rainbow-coloured cloud?

When the sun is at the ideal angle, light is reflected off of the ice crystals and water droplets in the cloud, giving the Pileus its rainbow-like hues. However, these clouds typically only exist for a short while. This is due to the fact that the cloud above them is "eating" them up, while Pileus is convectively absorbed by the lower cloud.

Difference between Pileus and Lenticular clouds

Cloud-spotters love to find pileus clouds. They aren't very common, but on days when you might expect cumulus clouds to develop into thunderstorms, you can spot them if you know where to look. Even though pileus cloud formations rarely last for more than a few minutes, they can be incredibly beautiful. They should not be confused with their close relative, the lenticular cloud.

While pileus clouds are a component of cumuliform clouds, lenticular clouds exist independently. Due to their resemblance to lentils, lenticular clouds are easily distinguished from other cloud species by their distinctive UFO shape and smooth edges.