Storm Henry brings colourful nacreous clouds
What is it they say? Every dark cloud has a silver lining? Storm Henry was predicted to bring high winds and heavy rain (as though we haven’t had enough of that in the 3 months since they started naming storms) to which Henry didn’t disappoint. However Scotalnd wasn’t prepared for the beautiful nacreous cloud displays it brought as well. Twitter and Facebook were inundated with stunning pictures of this phenomenon.
Nacreous clouds, also known as mother of pearl clouds, were seen last night from Perth as well as most other towns in Scotland.
Nacreous clouds form in the lower stratosphere over polar regions when the sun is just below the horizon. The iridescent nacreous clouds are as captivating as they are rare.
These eye-catching rainbow coloured clouds form in the Earth’s stratosphere at around 70,000ft, way above where other clouds are normally found and in much colder air, around -78C.
The BBCs weather presenters explained it is far too dry at this height for clouds to form, but during the polar winter the temperature can drop low enough to promote the cloud’s development.
“Here in Scotland, the recent storms have probably helped too, with strong winds driving moisture up into the stratosphere.
“Their colour comes from ice crystals refracting the sun’s rays to give the rainbow effect.”
He added: “They’re most vivid before dawn and after sunset, as they’re in sunlight longer due to their altitude. They’re sometimes referred to as ‘mother of pearl’ clouds or otherwise known as polar stratospheric clouds.”