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The Spring 2011 issue of The Earth Scientist is focused on modernizing seismology education. Thanks to IRIS, you can download this issue for free as a pdf. Print copies are available in our online store.
This is a photograph of altostratus clouds.
Click on image for full size
Courtesy of Keith G. Diem. Used by permission.

Altostratus

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.


Last modified September 25, 2007 by Becca Hatheway.

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