Nacreous clouds usually form in very cold conditions over polar regions and within the stratosphere, far above our normal clouds. One of the highest clouds, they are often referred to as "mother ...

They are actually a rare cloud called nacreous clouds or polar stratospheric clouds, they are also known as mother of pearl due to their iridescent appearance. They occur in the winter polar ...

"They form in the lower stratosphere over polar regions when the Sun is just below the horizon. The ice particles that form nacreous clouds are much smaller than those that form more common clouds.

A cold wave sweeping through the Arctic brought the rare polar stratospheric clouds ... news outlet Live Science. The clouds, which also go by the name of nacreous clouds, appear only in extremely ...