The Season of Blue Auroras

‘TIS THE SEASON FOR BLUE AURORAS: Blue auroras are very rare. Even veteran aurora chasers with years of Arctic experience have seldom seen them. Yet there is a time of year when they become easier to find–and that time is now.

“Last night, a blue aurora appeared overhead,” reports Geir T. Birkeland Øye of Ørsta, Norway, less than 200 miles south of the Arctic Circle. “This is a sight we don’t often see.”

Polar Stratospheric clouds (Nacreous clouds) Taken by Vincent Phillips on December 21, 2023 @ Hale village near Liverpool UK (Spaceweather.com Gallery) A small gap in storm Pia’s cloud cover just after sunset tonight revealed a stunning display of Polar Stratospheric clouds (Nacreous clouds) these rare clouds are normally only seen within the Arctic circle, the clouds form when the temperature in the Earth’s stratosphere becomes extremely low. (View from Hale village near Liverpool UK looking west just after sunset)

SPACEWEATHER.COM News: December 22, 2023

PSCs SPILL OUT OF THE ARCTIC: Normally, polar stratospheric clouds (PSCs) are confined inside the Arctic Circle. Only above the poles can the stratosphere become cold enough to create these rare clouds. However, during this week’s outbreak of PSCs, the clouds have spilled out of the Arctic to places they are seldom seen. Last night, Vincent Phillips witnessed their aurora-like colors near Liverpool, UK.

Widely considered to be the most beautiful clouds on Earth, polar stratospheric clouds are a sign of extreme cold. PSCs form when the temperature in the Arctic stratosphere drops to a staggeringly-low -85 C. Then, and only then, can widely-spaced water molecules in the dry stratosphere coalesce into tiny ice crystals. High-altitude sunlight shining through the crystals creates intense iridescent colors that rival auroras.

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