VOLCANIC ERUPTION IN ICELAND (UPDATED): Iceland's latest volcanic eruption is subsiding with lava flows today only 25% of yesterday's peak. Meteorologists say that the Grindavík volcano did not spew a plume of gas and dust into the high atmosphere; air travel should be unaffected and there won't be any exotic sunsets. Coincidentally, the Grindavík volcano is only 4.5 miles from the Geldingadalur volcano, which erupted in 2021 and produced a viral aurora photo.
AN OUTBREAK OF POLAR STRATOSPHERIC CLOUDS: A cold wave just swept through the Arctic stratosphere. Really cold. We know because on Dec. 17th these colorful clouds appeared over Sweden:
Above: A "PSC selfie" by Lights over Lapland driver Dimitrios Roukounakis
"It's that magical time of year again," says Chad Blakley, owner of the aurora tour guide service Lights over Lapland in Abisko, Sweden. "We just witnessed a spectacular display of polar stratospheric clouds."
Widely considered to be the most beautiful clouds on Earth, polar stratospheric clouds (PSCs) are rare. Earth's stratosphere is very dry and normally it has no clouds at all. 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 begin to coalesce into tiny ice crystals. High-altitude sunlight shining through the crystals creates intense iridescent colors that can rival auroras.
NASA forecast models of the polar stratosphere show that temperatures have indeed dropped into the very low range required for colorful Type II PSCs:
Above: Note the temperature dip inside the highlighted yellow oval
During a typical Arctic winter, PSCs appear no more than a handful of times, and the first sightings usually come in January. The apparition on Dec. 17th marks an early start, and may herald many more PSCs to come. Stay tuned!
more images: from Pekka Lähteenmäki of Helsinki, Finland; from Alan C. Tough of Elgin, Moray, Scotland
Realtime Space Weather Photo Gallery
Free: Spaceweather.com Newsletter
CHRISTMAS GIFTS FROM THE EDGE OF SPACE: Are you looking for a far-out Christmas gift? Check out the Earth to Sky Store. It's filled with unique items that have flown to the edge of space onboard cosmic ray research balloons.
Carried aloft by giant helium balloons, these unique gifts have flown above 99.7% of Earth's atmosphere, experiencing space-like blasts of cosmic rays, extreme cold, and a wild ride parachuting back to Earth after the balloon explodes. Even Amazon doesn't carry items this far out.
Don't forget to enter coupon code "BUZZALDRIN" at checkout for a 10% holiday discount.
Far Out Gifts: Earth to Sky Store
All sales support hands-on STEM education
Realtime Aurora Photo Gallery
Free: Spaceweather.com Newsletter
Realtime Comet Photo Gallery
Free: Spaceweather.com Newsletter