Lenticular Cloud Above Southern Utah University

June 04, 2018


Photographer: Maya Akpinar 
Summary Author: Maya Akpinar 

I noticed this lenticular cloud while standing on the roof of the science building at Southern Utah University. The temperature, wind flow and moisture were uncharacteristically variable for early April in southern Utah. The air was moist and breezy, and I could see the other clouds moving past this lenticular formation. It was not going to be long-lived, so I quickly grabbed my phone and took this shot.

Lenticular clouds are a particular favorite of mine. I first learned about them on Earth Science Picture of the Day. Technically called altocumulus lenticularis, understanding exactly how they form can be a little tricky. Most sources indicate that lenticular clouds form when warm, stable air moves up a mountainside, is pushed over the top to the other side where it then sinks, cools and creates a sort of pool of condensation on the downwind, protected side of the mountain.

But why are these clouds lens-shaped or in this case, spaceship-shaped? When the wind moves up and over the mountain it creates a wave pattern on the other side. At the crest of the wave the temperature is often lower than at the trough of the wave. This is because as air rises it cools. If the temperature drops to the dewpoint (the temperature at which condensation occurs) then you get a cloud forming near the crest of the wave only. The cloud continually forms in the space near the crest; then it sinks until reaching the trough of the wave where the air is warmer and the dew point is lower. This causes the cloud to vaporize at the bottom of the trough and thus once again disappear, creating the flat bottom to the cloud. For this reason, the lenticular cloud is usually stationary. It’s like an eddy in a river that forms behind a rock. The diagram is two-dimensional, but if you imagine this occurring in three dimensions, then you can visualize how the atmospheric activity just described can result in disc-shaped, stationary clouds, like the one in my picture. The mountain that created the waves allowing this cloud to form is Cedar Mountain, just to the east of Southern Utah University. Photo taken on April 5, 2018.

Photo Details: Camera: Apple iPhone SE; Software: Adobe Photoshop Lightroom 6.10.1 (Macintosh); Exposure Time: 0.0002s (1/6000); Aperture: ƒ/2.2; ISO equivalent: 25; Focal Length (35mm): 78.