Cumulus clous usually have a puffy "cotton-like appearance", with noticeable vertical development and clearly defined edges. They can be found alone, in lines, or in clusters. Factors like instability, moisture, and temperature gradient, make cumulus clouds precursors of many other types of clouds, e.g cumulonimbus clouds. In some cases these clouds can be associated with dust devils, landspouts, waterspouts and tornadoes. Cumulus means heap or a pile in Latin.