Earlier this year, researchers said the ozone over the region was recovering ... could have led to a heightened formation of polar stratospheric clouds, allowing chlorofluorocarbons to react ...

Nacreous clouds, or ice polar stratospheric clouds, are a rare type of cloud that forms in very cold conditions and at high altitudes. They are known for their iridescent colors, which are created ...

Stratospheric clouds over the Arctic may explain the differences seen between the polar warming calculated ... said Tuesday that the ozone hole over Antarctica has swelled to its largest size ...

A strong polar vortex is characterized by powerful, circular winds and extremely cold temperatures — conditions that caused a hole bigger than North America to open over Antarctica last year.

Fredrik Broms' photograph of the polar stratospheric clouds over Norway. These rare clouds are caused by ice crystals far up in the freezing stratosphere. Fredrik Broms' photograph of the polar ...

This is over ... Polar Vortex where they stay chemically inactive in the darkness. Temperatures in the vortex can fall to below -108 degrees Fahrenheit and ice crystals in Polar stratospheric ...

Photographers have captured breathtaking photos of “rainbow clouds” shining in the clouds. The multi-colored clouds are known as polar stratospheric ... PSCs form over some hilly mountains.

Strange "rainbow clouds" that look like a colorful portal to another dimension have recently appeared across northern skies. These nacreous clouds, also known as polar stratospheric clouds ...

So-called polar stratospheric clouds were seen over Norway, Sweden, Finland, Alaska, and Scotland. Some saw the clouds for three days in a row, a very rare occurrence. Arctic observers were ...