Residents of Douglas in Arizona have been treated to a rare and stunning phenomenon - fire rainbows.

Caused when ice crystals splits sunlight into different colours, they cause the sky to flicker with colour.

Brandon Rios, who captured the amazing images with his father, said he was 'completely astonished' by the phenomenon.

Fire Rainbow
© Brandon Rios/Rex Features
Fire rainbows, known by the proper name of circumhorizon arc, occur when the sun hits plate shaped ice cystals in the clouds, causing the colours of sunlight to separate.
'Although my father was the one to take the pictures I was with him at the time,' said Brandon after the pair spotted the rainbows over their home in Douglas, Arizona.

'He was going to get something that he left at work and when we came outside we were greeted by this beautiful sight.

'I was completely astonished to see a rainbow mixed in with the clouds.

'I didn't think something like this can exist.'

The clouds are seen several times a year in the US, although they are rare elsewhere in the world.
Fire Rainbow_1
© Brandon Rios/Rex Features
The colours appear to flicker in the sky and sunlight passes through the ice crystals.
Fire rainbows, known by the proper name of circumhorizon arc, occur when cirrus clouds are far enough up in the air to form plate-shaped ice crystals.

They are not actually rainbows, but a halo effect, although they are commonly referred to as fire rainbows.

When the sun is at the right angle it hits the top of these plates and splits into different colours that are viewable on the ground.
Fire Rainbow_2
© Brandon Rios/Rex Features
The flickering cloud rainbows form a variety of almost hypnotic shapes in the sky.
Fire Rainbow_3
© Brandon Rios/Rex Features
The phenomenon appears several times a year over the US, although is rare in Europe.