There are 10 basic clouds as identified by NWS: Cirrus (Ci), Cirrocumulus (Cc), Cirrostratus (Cs), Altocumulus (Ac), Altostratus (As), Nimbostratus (Ns), Cumulus (Cu), Stratocumulus (Sc), Stratus (St), and Cumulonimbus (Cb). (More info can be found here).
However in 2017, 11 more were added: Volutus, Asperitas, Fluctus, Cavum, Flumen, Cataractagenitus, Flammagenitus, Homogenitus, Silvagenitus, Cauda, and Murus.
I wonder how this one was classified.
More info on all the clouds you’d ever want can be found here – thanks NWS.