An "asperatus" cloud rolls over New Zealand's South Island in an undated picture. This apparently new class of clouds is still a mystery. Photograph courtesy Merrick DaviesExperts suspect asperatus clouds' choppy undersides may be due to strong winds
Nicknamed the Jacques Cousteau clouds, undulatus asperatus is a cloud formation proposed two years ago as a separate cloud classification by Pretor-Pinney, British cloud enthusiast and founder of the Cloud Appreciation Society.
rainbow Nacreous Clouds - Iceland - Polar stratospheric clouds or PSCs, also known as nacreous clouds (from nacre, or mother of pearl, due to its iridescence), are clouds in the winter polar stratosphere at altitudes of meters.
rain falling from a summer thunderstorm backlit by lightning, stars are visible in the night sky above the storm, and the canyon is lit by a nearly full moon, Grand Canyon National Park, summer photo copyright by Adam Schallau
Moonlight: And when you look up to the sky and see the sun, the moon and the stars—all the heavenly array—do not be enticed into bowing down to them and worshiping things the Lord your God has apportioned to all the nations under heaven.
Shelf cloud, Minnesota, US. When seen from the ground shelf clouds appear as low, wedge-shaped clouds and are usually associated with severe thunderstorms Photograph: Science Photo Library/Rex Features