They are some seriously weird looking clouds. Sometimes likened to UFOs, lenticular clouds are usually created by gravity waves. And when the last sunset rays shine right on them, they really look like something out of this world like in these pictures captured over Anza-Borrego-Desert State Park in Colorado Desert of Southern California on April 8, 2018.
Formation of lenticular clouds
Named for their smooth, lentil-like appearance, altocumulus lenticularis clouds are believed to be one of the most common explanations for UFO sightings.
These spooky forms appear downwind of mountains. When moving air encounters an obstacle like a mountain, it is forced to rise up and over it. As the air spills over the other side, the pull of gravity causes it to overshoot a little before resurging back up. It’s a bit like a car’s suspension bouncing after hitting a speed bump. A stable air mass will continue to rise and dip for a little while as it travels away from the mountain, setting up an invisible “standing wave”.
Lenticular clouds form when the airflow streaming over the mountain is both stable and humid. As it flows upwards and cools, the moisture in the air condenses to form clouds at the crests of the standing wave.
Lenticular clouds can also be caused by other speed bumps, such as tall thunderclouds, but because they often form on the downwind sides of mountains, they are also known as lee clouds, wave clouds or lee wave clouds.
A lenticular cloud is one of my favorite cloud formation. What are your favorite clouds?