Residents of Cape Town took to social media last weekend posting weird and wonderful photographs of stacked clouds resembling ‘UFO’s’.

Known more scientifically as Lenticular clouds, they created quite a stir! And if you don’t know what Lenticular clouds are, don’t worry, you’re not alone!

Lenticular clouds form when high winds blow over rough terrain, such as mountains and valleys. Scientifically, they are defined as ‘stationary lens-shaped clouds that form in the troposphere, normally in perpendicular alignment to the wind direction. Lenticular clouds can be separated into altocumulus standing lenticularis (ACSL), stratocumulus standing lenticular (SCSL), and cirrocumulus standing lenticular (CCSL). Because of their shape, they have been offered as an explanation for some Unidentified Flying Object (UFO) sightings.’

More common than you think, Lenticular clouds have been regularly confused for UFOs throughout history. They appear as smooth, round or oval lens-shaped structures, often appearing singular or stacked like pancakes.

According to AccuWeather Meteorologist Jesse Ferrell, lenticular clouds are formed when air moves over mountains, cooling sufficiently for condensation to take place. Lenticular clouds are different from other clouds because they don’t move, he said.

‘They are continually reformed over the same location by new air rising up and over a mountain, condensing and producing the clouds,’ Ferrell said.