Air normally moves significantly more horizontally than vertically. When moist air is forced upwards over a high geographic feature like a mountain or volcano, lenticular clouds can form as the air cools and water moisture condenses.
A type of wave cloud, the word lenticular originates from the Latin word Lenticularis which means lentil-shaped. Because they appear to cap or hang over mountain tops, these clouds are also often referred to as “cap clouds” or “UFO clouds” (after the cloud’s flying saucer-like shape).
As fast moving horizontal air meets a topographic barrier like a mountain, the air is forced up and over the mountain. The rising air cools at the top of the mountain and condenses water vapor in the air, forming the curved and layer shapes typical of a lenticular cloud.
Using Lenticular Clouds to Study Gravity Waves
As air rushes over mountains, gravity waves can form under the right conditions. Lenticular clouds can form at the crest of the gravity waves if the conditions of cold air and water vapor are present.
Satellite imagery captured this lenticular cloud forming over the top of Mount Michael, an active stratovolcano in the South Sandwich Islands.
Lenticular clouds can be commonly seen around the Rocky Mountains in the United States.
Hansen, K. (2021, January 19). Curious clouds in the Transantarctic mountains. NASA Earth Observatory. https://earthobservatory.nasa.gov/images/147772/curious-clouds-in-the-transantarctic-mountains
LeFevre, K. (2020, December 28). The case of the missing waves. Earthdata. https://earthdata.nasa.gov/learn/sensing-our-planet/the-case-of-the-missing-waves