Very rare polar stratospheric clouds of type II are observed over Scandinavia

The northern regions of Scandinavia on January 17, 2022 witnessed a rare high-altitude spectacle, according to photographer Adrien Moduy.

For about 2 hours, rare polar stratospheric clouds (PSO) of type II appeared out of nowhere, showing a stunning rainbow glow contrasting with the dimmer twilight of the short polar day.

PSCs are also called mother-of-pearl or mother-of-pearl clouds because their iris (the diffraction of sunlight on tiny ice particles) is one of the strongest in clouds on Earth.

Their strong colors are very clearly visible to the naked eye, which makes the impression surreal, almost like from a fairy tale.

These are also some of the tallest clouds on Earth, they form at an altitude of 15-30 km (9-18 miles) under very precise conditions limiting their appearance.

It should be very cold up there, which is possible only in the winter months over the polar regions, where the stratosphere is coldest. There, tiny ice particles (along with other chemicals present in Type I) originate and form over mountain ranges due to vertical shifts/strong winds, forming lenticular structures (type II).

"I took them off yesterday in a hurry between snow showers, as a friend warned me. I used a large focal length to emphasize their iridescence," says Adrian.

"In one of the episodes you can also see Jupiter hanging above the clouds (in the upper left corner!), as well as a flying plane! Everything was shot on a Sony a7rII camera with a focal length of 200 - 600 mm (Sony)."