Undulatus asperatus (or alternately, asperatus) is a cloud formation, proposed in 2009 as a separate cloud classification by the founder of the Cloud Appreciation Society. If successful it will be the first cloud formation added since cirrus intortus in 1951 to the International Cloud Atlas of the World Meteorological Organization. The name translates approximately as “roughened or agitated waves”.

A man dressed as Santa Claus poses during a base flying event in downtown in Berlin December 6, 2014. Participants of the event hosted by entertainment agency Jochen Schweizer flew down 98 metres (322 ft.) from atop the hotel in the German capital. (Photo by Hannibal Hanschke/Reuters)

Mothers-to-be show their belly paintings in Hefei, east China's Anhui province on May 8, 2020. (Photo by Rex Features/Shutterstock/China Stringer Network)

A koala soaked by floodwaters sits atop a fence post to escape the deluge in the town of Stirling in the Adelaide Hills of South Australia in this picture taken September 14, 2016. (Photo by Russell Latter/Reuters)

Tony Hilliard, left, and his family expose themselves to the elements as Hurricane Ida begins to make landfall, Sunday, August 29, 2021, in New Orleans, La. (Photo by Eric Gay/AP Photo)

A Ukrainian gunner sits in his 2S1 Gvozdika (122-mm self-propelled howitzer) on the front line in Southern Ukraine on October 8, 2022, amid the Russian invasion of Ukraine. (Photo by Dimitar Dilkoff/AFP Photo)

People are reflected in mirrors as they walk in a busy shopping district in Tokyo, Japan, December 25, 2015. (Photo by Thomas Peter/Reuters)

Seth Casteel is an award-winning photographer and the New York Times Best Selling Author of Underwater Dogs. His new book, Underwater Puppies, was published September 16, 2014. Photo: “Underwater Puppies”: Popcicle. (Photo by Seth Casteel)