Polar explorers of the 30th Antarctic expedition managed to see a beautiful and rare phenomenon - mother-of-pearl clouds.

We saw similar photos of rainbow-like clouds in early 2023, too. These rare rainbow clouds, more scientifically known as nacreous clouds, only appear in extremely cold weather conditions.

Dear Tom,What are mother-of-pearl clouds?—Oscar Johns, WilmetteDear Oscar,They are polar stratospheric clouds, also known as nacreous clouds or simply pearl clouds. They are rare, high altitude ...

The clouds, which also go by the name of nacreous clouds, appear only in extremely cold weather. They are created by tiny ice crystals that scatter sunlight creating little rainbows in the sky.

To understand how clouds get their shape, it helps to understand the basics of how they form. When air rises and cools, the water vapor it holds condenses into tiny water droplets or ice crystals.

Nacreous clouds appear over McMurdo Station in Antarctica. (Photo courtesy: Jeff Fogg) Issaquah's Jeff Fogg has been working down at the McMurdo Station in Antarctica for nearly a year and a half ...

Type II PSCs are often referred to as nacreous clouds because their iridescent hues can sometimes resemble nacre, also known as mother of pearl, which is produced in the shells of some mollusks.

Mother-of-pearl or “nacreous” clouds, require unusual conditions to form — very cold temperatures in the atmosphere, in a high altitude band of about 20-30 kilometres (12-19 miles).

Nacreous clouds are seen over Antarctica. Alan Light/Wikipedia This story was updated Nov. 26 at 8:10 p.m. EST. Second in a two-part series. Click here for part one.