Arcus cloud#Roll cloud

A roll cloud is a deep, horizontally aligned Arcus cloud in the form of a roll, which occurs mainly in connection with thunderstorms and, in particular, gust fronts, rarely also with cold fronts.

Roll cloud is a meteorology internationally recognized anglicism and can be translated with roll cloud, in the German language is for them but rather vague term for the squall usual. You carry this name because it appears to the observer as if the roll across the sky and thereby rotate about a horizontal axis. They should therefore not be confused with the much smaller and more vertically oriented funnel clouds. In addition, they are generally associated with strong gusts on its front to downbursts.

Roll clouds are quite rare and have no connection to the original thunderstorm cell or other cloud formations in contrast to the related to them on shelf clouds.

A famous especially among glider pilots roll cloud is the Morning Glory cloud that can be seen regularly on the north Australian Gulf of Carpentaria.