Undulatus Asperatus, a new cloud type
In an attempt to codify cloud vocabulary and aid in weather prediction, the World Meteorological Association (WMO) published the first International Cloud Atlas in 1896. The Atlas divides clouds into 10 genus, 26 species, and 31 varieties, and includes important tips for cloud identification as well as appropriately whimsical descriptions—cloud species range from praecipitatio, “to fall (down a precipice)” to castellanus, “a castle of a fortified town.” Though many updates and new editions have been published since, no new cloud types have been added to the Atlas since cirrus intortus (“an entangled lock of hair”) was added in 1951. Until now.
http://www.slate.com/blogs/atlas_obscura/2014/10/10/undulatus_asperatus_a_new_cloud_type.html