Stratus clouds are composed of thin layers of clouds covering a large area of the sky. This is simply mist or fog when it forms close to the ground. You can easily distinguish a stratus cloud by the long horizontal layers of cloud which have a fog-like appearance.
Stratus
The clouds form from large air masses that rise to the atmosphere and later condense. These are pretty benign in terms of rainfall producing light showers or even light snow if the temperatures fall below freezing. However, if enough moisture is retained at the ground level, the cloud can transform into a nimbostratus. Stratus clouds are very common all over the world most especially in the coastal and mountainous regions.
Stratocumulus
Stratocumulus looks like a thick white blanket of stretched out cotton. They resemble cumulus clouds except they’re far bigger. The base is well-defined and flat but the upper part of the cloud is ragged due to convection with the cloud itself. Depending on the thickness of the cloud, a stratocumulus will have light to dark gray hues. People often think rain is imminent when they see these clouds. In reality, you’ll be lucky to get a light drizzle out of them.
Altostratus
Altostratus clouds are “strato” type clouds (see below) that possess a flat and uniform type texture in the mid levels. They frequently indicate the approach of a warm front and may thicken and lower into stratus, then nimbostratus resulting in rain or snow. However, altostratus clouds themselves do not produce significant precipitation at the surface, although sprinkles or occasionally light showers may occur from a thick alto- stratus deck.