Image Credit: Photograph by Alan Tough.
In late January and early February 2016, unusually cold Arctic stratospheric air reached down as far as the United Kingdom.
This triggered sightings of rare and beautiful Polar Stratospheric (Nacreous) Clouds (PSCs).
I had to go down to Alloa for a course and took an old compact digital camera with me, just in case any displays were visible from that part of the country.
PSCs have a sinister side, though: chemical reactions on the surface of the clouds destroy ozone.