A Lenticular Cloud Over New Zealand

What's happening above those mountains? Several clouds are stacked up into one striking
lenticular cloud. Normally, air moves much more horizontally than it does vertically.
Sometimes, however, such as when wind comes off of a mountain or a hill, relatively
strong vertical oscillations take place as the air stabilizes. The dry air at the top of an
oscillation may be quite stratified in moisture content, and hence forms clouds at each
layer where the air saturates with moisture. The result can be a lenticular cloud with a
strongly layered appearance. The above picture was taken in 2002 looking southwest
over the Tarurua Range mountains from North Island, New Zealand.