Elusive 'Green Flash' spotted at sunset along the Washington coast

SEABROOK, Wash. -- A Seattle National Weather Service forecaster taking a break along the coast may have been able to escape the hustle and bustle of the city, but couldn't escape the wonders of atmospheric science.

Dana Felton captured this rare and elusive showing of the "Green Flash" as the sun set over the Pacific Ocean on Wednesday.

The speck of green usually only lasts for an instant -- maybe a second or two -- and requires a rather complex atmospheric set up to occur which makes the sightings quite rare.

First you need a flat horizon (usually out over large bodies of water is best).

After that? The great Atmospheric Optics site takes a stab at explaining it: "A standard stable atmosphere gets cooler with increasing height and the air density falls smoothly and monotonically. The lower and denser portion acts as a giant lens bending rays from the setting sun towards the earth. As a result, the rays appear to be coming from a point higher in the sky and the sun appears to be raised up. Green light is refracted more strongly than red and so different colored images of the sun become very slightly vertically separated. As the sun sinks it develops a green upper edge and a red lower one."

But remember -- don't go starting at sunsets without eye protection looking for the flash. Even an instant can cause damage.