Stratus Opacus

Above: Stratus Opacus

Stratus Opacus

Stratus opacus clouds, one of the varieties of stratus clouds, belong to the category of low-level clouds along with stratus translucidus and stratus undulatus. All species and varieties of stratus clouds, including stratus opacus clouds, have a uniform base and form horizontally layered. They are also colored gray, light gray or close to white and they bring about a cloudy day in the areas where they form.

How do stratus opacus clouds look like?

Stratus opacus clouds look like any other stratus clouds that are flat and have no features at all unlike other cloud types which when seen in the sky usually comes in different forms and sizes sometimes resembling different animals or creatures. Because they are uniformly structured and are sheet-like, they almost entirely cover the sky and blocks out the sun in the area. The difference with other stratus cloud varieties is that, stratus opacus as can be gleaned from its name makes the sky look misty, foggy or hazy. These are different with stratus translucidus that are translucent in appearance making the sky look glassy. Stratus undulatus, on the other hand, look like undulating waves but still have a uniform base.

How are stratus opacus clouds formed?

Stratus opacus just like the other species and varieties of stratus clouds are formed either through two cooling processes called advective or radiative cooling. In advective cooling, the large air mass which would eventually become the stratus opacus clouds is cooled because it moves from a warmer area to a cooler one. Radiative cooling, however, happens when the large air mass becomes cool due to radiation.

In both cooling methods, the process is basically the same. A large air mass becomes warm because it passes through an area on the surface of the sea that is warm. As it is being warmed, it picks up water vapor. The large air mass undergoes advective cooling as it is pushed by the wind over the cool sea surface or radiative cooling as it passes through a radiation-filled area. As it is being cooled, the air mass forms small droplets. The cooled air mass is then moved upwards to the atmosphere and becomes stratus clouds eventually becoming one its species or varieties like stratus fractus, stratus nebulosus, stratus opacus, stratus translucidus or stratus undulatus as the case may be.

What height is stratus opacus clouds formed?

The height in which stratus opacus clouds are formed are influenced by the following facts:

  • Stratus opacus clouds are low-level clouds under the category of stratus clouds.


  • Being a low-level cloud, stratus opacus clouds are the most seen cloud variety forming relatively lowest among the different cloud types in the troposphere.


  •  As such, they are formed up to a height of about 6500 feet or 2000 meters only.

Classification of stratus opacus clouds

Stratus opacus clouds are classified as low-lying                 clouds under the family of stratus clouds. It is one among the three varieties of stratus clouds. The other two are stratus translucidus and stratus undulatus. As such, the two species of stratus clouds can be stratus nebulosus opacus or stratus fractus opacus.

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