Fire rainbows are the rarest of all naturally occurring atmospheric phenomena. For a fire rainbow to occur, cirrus clouds must be feet in the air with the precise amount of ice crystals, and the sun must hit the clouds at 58 degrees.
Heavenly haze: Remarkable rainbow cloud towers over Mount Everest
The stunning image is of a rainbow cloud, captured above Mt Everest by Oleg Bartunov whilst on an expedition in the Himalayas, Nepal. The amazing rainbow effect is created when tiny ice crystals in the water vapour of the clouds reflect the sunlight.
Nacreous Cloud over NASA Dome, Antarctica. These clouds are formed in the winter polar stratosphere at altitudes metres. Particles within the optically thin clouds cause coloured interference fringes by diffraction.