What is behind it?

This “UFO cloud” always appears in the same place

(Bild: NASA/Landsat 8/OLI)

The US space agency NASA recently published a photo on its website of a highly unusual cloud that keeps appearing in the same place over New Zealand's South Island and is sometimes misinterpreted as a UFO. What is behind the phenomenon?

The cloud, which was recorded by the Landsat 8 satellite on September 7 from an altitude of around 700 kilometers, is a so-called lenticularis cloud (lens cloud). The special thing about the cloud, which repeatedly appears between the villages of Middlemarch and Hyde in the Otago region of the South Island, is that it practically always has the same shape.

Appears in the same place every time
The cloud, christened "Taieri Pet" by the locals, appears there again and again, remaining seemingly motionless over the area. This has to do with the special topography there. It always looks very similar and appears in practically the same place every time. The lenticularis cloud shown in the picture (see above) is about 11.5 kilometers long.

The lenticular lenticularis clouds form when the prevailing winds encounter a topographical barrier, such as a mountain range. The wind, which is forced to flow over the mountain range, creates a kind of wave in the atmosphere. At the crest of the wave, the air cools down and the water vapor it contains condenses into a cloud. 

Satellite has been orbiting in space for over eleven years
"Landsat 8" (pictured above) was sent into space on February 11, 2013 on board an "Atlas" rocket from California to monitor the Earth. The satellite orbits the earth at an altitude of 700 kilometers and provides data on natural disasters and the condition of forests, among other things.