This is a photograph of altostratus clouds.
Click on image for full size
Courtesy of Keith G. Diem. Used by permission.
Altostratus clouds (weather symbol - As) consist of water and some ice crystals. They 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 it hits the ground,
then the cloud becomes classified as a nimbostratus cloud.
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