In March, the World Meteorological Organization added some new cloud-types to its International Cloud Atlas for the first time since 1951.
One such was Asperitas, describing “well-defined wave-like structures in the underside of the cloud; more chaotic and with less horizontal organisation than the variety Undulatus”.
Hobbyists and cloud enthusiasts have been agitating for the new type to be recognised for several years, under the name undulatus asperatus. The video above shows one formation looming hypnotically over Nebraska, USA, in 2014. The cloud base swells and melts, pinched into wavy peaks like an inverted imitation of a stormy seas.
The formations are particularly common over the southern plains of the US, often during the day, following a thunderstorm. They don’t necessary herald more bad weather, despite their thrillingly apocalyptic appearance.
Originally published by Cosmos as A wild new kind of cloud
Curated content from the editorial staff at Cosmos Magazine.
Read science facts, not fiction...
There’s never been a more important time to explain the facts, cherish evidence-based knowledge and to showcase the latest scientific, technological and engineering breakthroughs. Cosmos is published by The Royal Institution of Australia, a charity dedicated to connecting people with the world of science. Financial contributions, however big or small, help us provide access to trusted science information at a time when the world needs it most. Please support us by making a donation or purchasing a subscription today.