'Rare, beautiful and destructive'

That's what I've just read about these nacreous, mother-of-pearl or polar stratospheric clouds, which are associated with severe winds and storms. Apparently they are a mixture of supercooled water, ice crystals and nitric acid, and are a major contributing factor in the formation of holes in the ozone layer in the Arctic and Antarctic.
I was really pleased to see them and get some photos as we drove to Bowness to go to the cinema.