On December 13, 2017, Chris Mannerino was at Sunset Cliffs Natural Park in San Diego, California when he looked out over the Pacific, and caught this spectacular double green flash. It’s what’s called an M-Mir or mock-mirage green flash, caused by one of the frequent temperature inversions off the California coast, which themselves result from warm Santa Ana air off the the land covering air that’s been cooled by an offshore ocean current. Read more about green flashes at Les Cowley’s website, Atmospheric Optics.
I wondered if the recent California wildfires had anything to do with this green flash, and Chris confirmed:
There was a fire southeast of Tijuana, and fire in the north county that were blowing off shore due to the Santa Ana winds.
And, indeed, Les Cowley told me by email that – although smoke doesn’t affect the formation of the flash – the smoke can attenuate the sun’s rays enough to reveal the flash details. As Chris said:
At least something good came from the fires.
Thank you, Chris, and Les!
Bottom line: Double green flash over the Pacific Ocean, off San Diego.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.