This rainbow aura is caused by a type of cloud called a pileus cloud (more commonly known as a cap cloud) which forms on top of rising cumulus clouds. Usually these colours are produced but drowned out by sunlight, in this picture shot in Ethiopia however the darker cloud is allowing the rainbow to shine through.(Image: Esther Havens)

This rainbow aura is caused by a type of cloud called a pileus cloud (more commonly known as a cap cloud) which forms on top of rising cumulus clouds. Usually these colours are produced but drowned out by sunlight, in this picture shot in Ethiopia however the darker cloud is allowing the rainbow to shine through.

(Image: Esther Havens)