What is a scud cloud?

Scud clouds are low, ragged cloud fragments that are sometimes visible below the base of a thunderstorm. They are usually detached from the cloud base and often flow with the wind. Scud clouds form as a result of a thunderstorm's outflow, as cold air rushes to the ground and forces warm, moist air upward. Although they do not produce severe weather, scud clouds are often mistaken for wall clouds, funnel clouds and even tornadoes. Formally, scud clouds are classified as stratus fractus or cumulus fractus clouds. Here are more pictures of scud clouds. (Answered by Sean Potter, a certified consulting meteorologist and science writer in Washington, D.C., September 12, 2005.  more