The sun was sinking in the west, behind the long curves of the distant Purbeck hills. The pale blue-grey and apricot sky showed thin streaks of high, icy clouds. To the right of the sunset, a seeming gap in the clouds began to shine with bright rainbow colours. Just a little patch of rainbow cloud and definitely not a bow of colour.
Looking up this phenomenon when we arrived home, we discovered that we had seen a rare iridescent cloud. Google images show many different and beautiful examples from around the world. Wikipedia describes the iridescent cloud as a "diffraction phenomenon".
Small crystals of ice in the cloud are individually scattering the light shining through them from the setting sun.Wikepedia continues:
"If parts of the cloud have crystals of a similar size, the cumulative effect is seen as colours."
Photograph taken using the "sunset" setting on my camera.
Using the automatic setting. The iridescent cloud is less visible in this shot but was quite startling to the naked eye. We were not the only people who pulled over into the hill top car park to take photographs.