mixing. Cumulonimbus clouds Cumulonimbus clouds are the final form of growing cumulus clouds. They form when cumulus congestus clouds develop a strong updraft that propels their tops higher and higher into the atmosphere until they reach the tropopause at in altitude. Cumulonimbus clouds, commonly called thunderheads, can produce high winds, torrential rain, lightning, gust fronts, waterspouts, funnel clouds, and tornadoes. They commonly have anvil clouds. Horseshoe clouds A short-lived horseshoe cloud may occur when a horseshoe vortex deforms a cumulus cloud. Extraterrestrial Some cumuliform and stratocumuliform clouds have been discovered on most other planets in the solar system. On Mars, the Viking Orbiter detected cirrocumulus and stratocumulus clouds forming via convection primarily near the polar icecaps. The Galileo space probe detected massive cumulonimbus clouds near the Great Red Spot on Jupiter. Cumuliform clouds have also been detected on Saturn. In 2008, the Cassini spacecraft determined that cumulus clouds near Saturn's south pole were part of a cyclone over in diameter. The Keck Observatory detected whitish cumulus clouds on Uranus. Like Uranus, Neptune has methane cumulus clouds. Venus, however, does not appear to have cumulus clouds. See also List of cloud types Notes References Footnotes Bibliography External links AMS Glossary of Meteorology Cloud types Articles containing video clips