Stratus cloud

Type of cloud

Stratus clouds are low-level clouds characterized by horizontal layering with a uniform base, as opposed to convective or cumuliform clouds formed by rising thermals. The term stratus describes flat, hazy, featureless clouds at low altitudes varying in color from dark gray to nearly white. The word stratus is derived from the prefix Strato- meaning 'layer'.

From Wikipedia, under CC BY-SA. More on occurri.