Lenticular, or lee wave, clouds form downwind of an obstacle in the path of a strong air current. In the Boulder, Colorado, area, the obstacle is the Front Range of the Rocky Mountains, seen through clouds at the bottom of the picture. Click on image for full size (32 Kb) Courtesy of UCAR Digital Image Library

Lenticular clouds form on the downwind side of air flowing over a large mountain or mountain range. Unlike most clouds that move across the sky, lenticular clouds stay in one place as air appears to blow through them. What is really happening is that the cloud forms on the side closest to the mountains where air is uplifting over the top of the mountain. Then the cloud moves with the wind and evaporates on the downwind side, so it appears stationary even though air is moving through the cloud.

As this photo on this page shows, lenticular clouds are lens-shaped and resemble flying saucers.

Lenticular, or lee wave, clouds form downwind of an obstacle in the path of a strong air current. In the Boulder, Colorado, area, the obstacle is the Front Range of the Rocky Mountains, seen through clouds at the bottom of the picture. Click on image for full size (32 Kb) Courtesy of UCAR Digital Image Library

Lenticular clouds form on the downwind side of mountains. Wind blows most types of clouds across the sky, but lenticular clouds seem to stay in one place. Air moves up and over a mountain, and at the point where the air goes past the mountaintop the lenticular cloud forms, and then the air evaporates on the side farther away from the mountains.

As this photo on this page shows, lenticular clouds are lens-shaped and look like flying saucers.

Lenticular clouds form downwind of an something that is in the path of a strong current of air. In this photo, the Rocky Mountains are in the path of the air current and help form these lenticular clouds. Click on image for full size (32 Kb) Courtesy of UCAR Digital Image Library

Lenticular clouds form near the tops of mountains. Wind blows most types of clouds across the sky, but lenticular clouds look like they stay in one place.

As this photo on this page shows, lenticular clouds look like flying saucers.