LOUISVILLE, Ky. (WAVE) - Undulatus asperitas (or Asperitas) is the most recent cloud formation to be added to the World Meteorological Organization's International Cloud Atlas. The last cloud formation to be added before undulatus asperitas was the cirrus intortus in 1951.
The word asperitas comes from the Latin root aspero, which means to “make rough or uneven.” Undulatus means wavy. The term Undulatus asperitas translates to an agitated wave.
Asperitas looks like ocean waves in the sky. The base of the cloud can be anywhere from 4,000 to 10,000 feet up.
How asperitas clouds form is still being researched. The current hypothesis is that their rippling appearance is connected to the aftermath of thunderstorms; however, they have been seen in calmer weather. There is a theory that asperitas clouds form when mammatus clouds (which look like udders hanging in the sky because of rising and falling air) drop into areas of the atmosphere where there is wind shear (a change in wind direction with height, which leads to the wave-like appearance and motion.