LENTICULAR CLOUDS

Lenticular clouds are characteristic of all mountain ranges and form in response to wind. When strong winds blow over the mountains and force moist air up to cooler elevations, the moisture condenses. As the winds blow back down the other side of the mountains, the moisture re-vaporizes. The lenticular cloud is the condensed (visible) moisture under the wind stream; it doesn't drift like other clouds do because it's "trapped" in a pocket of relatively calm air just below the wind stream and just above warmer air below. The notion that the clouds are stationary is an optical effect. A lenticular cloud actually is forming on one end (front edge) and vanishing on the other, giving the appearance that it is in a fixed position. Lenticular clouds assume distinct shapes, generally resembling a disc (hence giving rise to a common name of "pancake clouds" or in a flat elongated shape stretching parallel to the mountain range. Also see Clouds and Sierra Wave (Sierra Nevada Mountains).