The other day I was driving home from work, and on the south side of the Catalina Mountains in Tucson, I saw these clouds:
Unfortunately, because I took the picture with my iPhone, the clouds are a bit hard to see. But, if you look closely at the clouds in the center of the image, you’ll notice that they’re rounded and somewhat “flying saucer” shaped. Here’s a better picture of the same type of clouds, that I took in Mt Shasta, CA:
These types of clouds are called Lenticular clouds, and they are stationary, lens shaped clouds that form at high altitudes. Typically, these clouds form on the downwind side of a mountain where warm, moist air is flowing, creating a series of large-scale standing waves. If the temperature at the crest of the wave drops to the dew point, moisture in the air may condense to form lenticular clouds. As the moist air moves to the trough of the wave, if it’s warm enough, it may evaporate back to vapor. Under certain conditions, long strings of lenticular clouds can form near the crest of each successive wave, creating a formation known as a wave cloud. And, because these clouds have a characteristic lens appearance and smooth saucer-like shape, they are often mistaken for UFOs (or “visual cover” for UFOs).
The air in the area of lenticular clouds is great for gliders, who seek out and ride the updrafts associated with the standing waves, but not so great for pilots of powered aircraft who are concerned with the turbulence. “Wave lift” often found in areas with lenticular clouds is often so smooth and strong that gliders can sail to incredible heights and distances. In fact, the current gliding world records for both distance (over 3,000 km; 1,864 mi) and altitude (15,460 m; 50,721 ft) were set using such lift.
I’ve always loved how lenticular clouds look. In almost every trip past Mt Shasta in California, where I have been able to see the mountain, lenticular clouds are present. I’ve also noted them quite frequently on the top of Mt Rainier in Washington. They are very beautiful clouds, but you can rest assured there are no aliens hiding in them!