Undulatus asperatus aka “roughened or agitated waves”: This cloud formation has been proposed as a separate cloud classification by the founder of the Cloud Appreciation Society and would be the first new type of cloud recognised since 1951
Cloud Art or Nature's Cloud Symphonies: this multi-coloured cloud phenomenon is called Sundog: rainbow cloud when ice crystals appear in clouds & refract sun's rays. Photographer Robert Arn, here in Heyworth, Illinois, US
20 Spectacular and Bizarre Weather Phenomena that really exist - Mammatus clouds are cloud pouches that form and hang underneath the base of a cloud. When air and clouds holding different levels of moisture mix, the heavier one sinks below the lighter.
IT'S A SONIC RAIN BOOM! Circumhorizon Arc (aka Fire Rainbow) - an ice halo formed by ice crystals located in cirrus clouds. Light passes through the hexagonal crystals and if seen at the right angle forms a rainbow cloud.