Supercooled rainbow appears over Muonio, Finland
A supercooled rainbow was observed and photographed above Muonio, Finland on December 4, 2017. Supercooled rainbows were also sighted in the Arctic last year.
"I have never seen a rainbow during the winter and I didn't even know that it is possible for them to form when the temperature is below 0 °C [32 °F]," says Valtteri Immonen who took the photograph below. "It was -6 °C [21.2 °F], no rain and no snowfall. Yet there was a huge rainbow across the sky," Immonen said.
Supercooled rainbow captured over Muonio, Finland on December 4, 2017. Credit: Valtteri Immonen (via Spaceweather.com)
"The rainbow's appearance, narrow with a supernumerary, says that it was produced with reasonable size water drops, perhaps about 0.5 mm in diameter. I surmise that the there was high-level precipitation that did not necessarily reach the ground. The drops could also have been supercooled below the normal freezing point of water," Atmospheric optics expert Les Cowley told Spaceweather.com.
Supercooled raindrops can form when droplets of liquid waterfall through layers of subfreezing air, Dr. Tony Phillips of Spaceweather.com explains. Droplets containing specks of dust or even microbes readily freeze as ice crystals form around the impurities. But when rain droplets are especially pure, they can remain in a liquid state even when the temperature drops below freezing.
"Last winter, supercooled rainbows were sighted in the Arctic as strange weather gripped the poles," Phillips said.
"Immonen's photo suggests that more of these rare rainbows may be in the offing," he concluded.
Featured image: Supercooled rainbow captured over Muonio, Finland on December 4, 2017. Credit: Valtteri Immonen (via Spaceweather.com)
If you value what we do here, open your ad-free account and support our journalism.
Related articles
Producing content you read on this website takes a lot of time, effort, and hard work. If you value what we do here, select the level of your support and register your account.
Your support makes this project fully self-sustainable and keeps us independent and focused on the content we love to create and share.
All our supporters can browse the website without ads, allowing much faster speeds and a clean interface. Your comments will be instantly approved and you’ll have a direct line of communication with us from within your account dashboard. You can suggest new features and apps and you’ll be able to use them before they go live.
You can choose the level of your support.
Stay kind, vigilant and ready!
You can also support us by sending us a one-off payment using PayPal:
