Lenticular clouds 1
Fig. 12: People wearing aluminum foil hats may say that these are carmouflaged UFO's, but in reality those are lenticular clouds above a mountain summit. These clouds are formed by wet air pushed across a mountain so that they cool and water condenses. On the other side the air warms up again and the water drops evaporate again. — EXIF: Nikon D200; Δt=1/500 s; f=40 mm; f/14.0; ISO 200; 2009-01-04 12:13:58