« January 21, 2008 | Main | January 24, 2008 »

Tuesday, January 22, 2008

Saucers Over Switzerland


Click image for an enlargement.

A fine collection of lenticular clouds (altocumulus lenticularis) were visible above the Alps yesterday afternoon, 2008-01-21. These clouds are formed when moist air is forced upward by a mountain peak by wind pressure, condensing at the lower temperature of higher altitude. Unlike regular clouds, lenticular clouds stay in place over the peak(s) which cause them to form; these remained little changed over the hour I observed them.

These clouds often look like something produced by unwise use of the “clone brush” in an image editing program, but that's the way they are—this image has not been altered in any way apart from cropping and contrast adjustment. You can click the enlargement in the pop-up window to view the full resolution original in a scrollable window.

Posted at 16:31 Permalink