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January 09, 2020

Polar stratospheric clouds!


Polar stratospheric clouds above Abisko National park, Sweden from Lights Over Lapland on Vimeo.

The best Polar stratospheric cloud display in decades is currently happening. From Spaceweather.com...

Polar stratospheric clouds are rare. Normally, the stratosphere has no clouds at all. A few times each winter, however, icy clouds form when the temperature in the stratosphere drops below -85C. Such staggeringly-low temperatures are required to help sparse water molecules stick together. This winter, the clouds have been appearing daily since late December, a sign of unusually cold conditions in the stratosphere.

Stratospheric clouds are widely regarded as the most beautiful clouds on Earth. Because of their intense colors (caused by high-altitude sunlight hitting tiny ice crystals), novice sky watchers sometimes mistake the clouds for auroras.

Posted by Snaggy at January 9, 2020 10:47 AM