RARE NACREOUS CLOUDS spotted again in Scarborough. Rainbow-effect cloud formations. Nacreous clouds usually form in very cold conditions over polar regions and within the stratosphere, far above our normal clouds.One of the highest clouds, they are often referred to as "mother-of-pearl" formations. They are rarely spotted in the UK because of the exceptional conditions needed. Polar Vortex Nacrious cloud is mostly seen a couple of hours either side of sunset or sunrise. Occasionally, cold polar

China: Low-Hanging Black Clouds Cover City At Dramatic Sunset In Inner Mongolia

Cricwick - Clouds cover the Gabba right before the game ....