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This is a photograph of altostratus clouds.
Click on image for full size
Courtesy of Keith G. Diem. Used by permission.

Altostratus

Altostratus belong to the Middle Cloud group (2000-7000m up). An altostratus cloud usually covers the whole sky and has a gray or blue-gray appearance. The sun or moon may shine through an altostratus cloud, but will appear watery or fuzzy.

An altostratus cloud usually forms ahead of storms with continuous rain or snow. Occasionally, rain will fall from an altostratus cloud. If the rain hits the ground, then the cloud becomes classified as a nimbostratus cloud.


Last modified September 25, 2007 by Becca Hatheway.

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Rain

Rain is precipitation that falls to the Earth in drops of 5mm or more in diameter according to the US National Weather Service. Virga is rain that evaporates before reaching the ground. Raindrops form...more

Nimbostratus

Nimbostratus clouds belong to the Low Cloud (surface to 2000m up) group. They are dark gray with a ragged base. Nimbostratus clouds are associated with continuous rain or snow. Sometimes they cover the...more

Cirrocumulus

Cirrocumulus clouds belong to the High Cloud group (5000-13000m). They are small rounded puffs that usually appear in long rows. Cirrocumulus are usually white, but sometimes appear gray. Cirrocumulus...more

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The middle cloud group consists of Altostratus and Altocumulus clouds. Middle clouds are made of ice crystals and water droplets. The base of a middle cloud above the surface can be anywhere from 200...more

Cloud Formation Due to Weather Fronts

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Altocumulus

Altocumulus clouds are part of the Middle Cloud group (2000-7000m up). They are grayish-white with one part of the cloud darker than the other. Altocumulus clouds usually form in groups and are about...more

Altostratus

Altostratus belong to the Middle Cloud group (2000-7000m up). An altostratus cloud usually covers the whole sky and has a gray or blue-gray appearance. The sun or moon may shine through an altostratus...more

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