Shelf cloud is a low, horizontal wedge-shaped arcus cloud, usually associated with a thunderstorm gust front. Occasionally it goes together with a (occluded) cold front, even in the absence of thunderstorms. Unlike the roll cloud, the shelf cloud is attached to the base of the parent cloud above it. Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent, boiling, and wind-torn.

The picture was taken at sunset of an approaching occluded cold frontal systems which contained some TCU and CB clouds but without thunderstorm. On its passage strengthening winds and some light wintry precipitations were observed.