A GREEN FLASH OVER DRY LAND: Seaside photographers have a special fondness for the sunset. It’s the time of day for the green flash–a split-second pulse of verdant light that signals the disappearance of the sun beneath the ocean waves. But the sea is not always required. Yesterday in Treviso, Italy, Enrico Finotto was looking across dry land when he witnessed this magnificent green flash.
“It was a complete surprise,” says Finotto.
Atmospheric optics expert Les Cowley explains what happened: “This is a mock-mirage green flash produced by light rays bending as they cross a temperature inversion layer. Such flashes can happen over land as well as the sea. We see more flashes over the sea because the sea horizon is not obscured by hills or buildings. But land flashes can be just as spectacular.”
Moreover, dry land offers an advantage that the sea does not. “Over land you might also see a flash twice!” continues Cowley. “I saw once one from our garden, ran indoors and upstairs to see a repeat performance a few seconds later. Try this on a hill slope but be careful, it can be the stuff of heart attacks!”