The stunning image below 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. The sight is rare and has only been reported a few times previously.
Over the last couple of days, those of us in Ireland, England and Scotland have been lucky enough to view the rare and beautiful nacreous clouds brought in under the residual influence of Storm Geraldine. These clouds, also known as Mother of Pearl clouds, are more often seen in colder northern regions of Canada, Scandinavia and Iceland, and fall under the category of Polar Stratospheric Clouds (PSC). They form in the lower stratosphere under very cold conditions (approximately -85 degrees Celsius), and produce tiny ice crystals which diffract the light from the Sun, forming hypnotising, iridescent rainbows hues. The fact that these clouds often take the shape of a wave likens them to the stroke of a paintbrush. They are most visible just after dawn and sunset, so for anyone hoping to get a look at them, try to get outside when the Sun is low in the sky. These images were taken on Tuesday, 2nd February.