{%recommended 5016%}Storm chaser Mike Olbinski caught this unbelievable sunset full of the rare asperitas (also known as undulatus asperatus) cloud formation on the plains of North Dakota.
While cloud-watchers have been talking about asperitas clouds for years, it was only in March that the World Meteorological Organization gave them an official entry in the International Cloud Atlas. The WMO describes the clouds as “well-defined wave-like structures in the underside of the cloud; more chaotic and with less horizontal organisation than the variety Undulatus”.
