The Cloud Appreciation Society has been posting cloud pictures from around the world in their photo gallery for many years.
Around 2006, they began receiving submissions from around the globe of a cloud that didn't fit into any one classification. They began to refer to them as "another of those weird, nameless clouds," which can be seen below courtesy of cloudappreciationsociety.org.
The society decided to try and fix this by assigning them the unofficial name, asperatus. However, a cloud is not considered to be official until it appears in the World Meteorological Organization's International Cloud Atlas.
It will officially be added in the the International Cloud Atlas in early 2016. The WMO changed the name to "asperitas," after the Latin for "roughness." This is the first new cloud type since 1951.