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| Altostratus translucidis looking good at sunset behind the Washington State capitol dome. |
Now that we've moved a bit lower in the troposphere to the mid-level clouds (the fantastic new altocumulus
asperatus cloud type!), I thought I would brighten up everyone's screen/life with some warm glowing sunsets courtesy of our Cloud of the Week #6--
altostratus translucidis.
Though "alto" means "high," in meteorological circles it means "middle." So this Altostratus, typically forms at altitudes of 6,500 ft. to 23,000 feet. It assumes the basic form of a layer "stratus," and is therefore altostratus. There are four varieties of altostratus; this is the one that is thin enough (translucent) to show the position of the sun...even though it has just set.
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| Photo of altostratus sunset over Bellingham Bay, courtesy W.P Ruth |
Though you wouldn't know it from this photograph, altostratus is known among the cloud-spotting cognoscenti as the "boring cloud." In the middle of the day, these clouds do nothing photogenic or uplifting. They appear gray to bluish-gray and are often thick (thousands of feet thick) and extensive (several thousands of square miles). Altostratus are composed of both ice crystals and water droplets and so diffuse light in a manner similar to ground glass. If you think you are looking up at altostratus, but see your shadow on the ground, you're probably looking at a higher, thinner could--cirrostratus.
I guess I shouldn't have been surprised when I went rummaging through my files of cloud photographs and found none of altostratus by day. I have thousands of photographs of beautiful clouds, but now I will have to start collecting photographs of boring ones, too.
Next Up: The Accidental Naturalist reviews O'er the Land.
