Mini Cloud Atlas
Altostratus in the High Sierra
Altostratus and fractostratus during a light snowfall in the Sierras. It had been an unusually moist winter, with 5 to 6 feet of snow already on the ground. I took this photo from just under the top of a snow ledge behind a building, where the snow had been cleared to ground level so the back door could be used. Altostratus is the stratoform cloud type which occupies mostly middle layers of the troposphere, between the low levels (stratus) and high (cirrostratus). It is common in advance of both tropical and extratropical cyclones, and sometimes forms near large thunderstorm complexes.
Donner Pass CA (13 Mar 98) Looking SSE