Fata Morgana in Mountains of Montana

December 27, 2016

FataMorgana (1)

December 2016 Viewer's Choice

Photographer: Rod Benson
Summary Author: Rod Benson
The photo above showing the Rocky Mountains about 30 mi (48 km) northwest of Helena, Montana, was taken from the Continental Divide Trail on November 28, 2015. In the far background, a Fata Morgana (superior mirage) was present over the distant mountains. Fata Morgana is the Italian name for the Arthurian sorceress Morgan le Fay, is so-named because it was believed that she created the illusions of distant land, sometimes with castles, to lure sailors to their deaths.

Note the fog in the mid-ground that resulted when the temperature in the valley dropped below the dew point. A layer of relatively warm air lies above the cool air that drained into the valley overnight. This classic temperature inversion allowed the sorceress to do her handiwork. In reality, all mirages are due to refraction (bending, redirecting) of light from distant objects. As light waves pass through layers of air that have different densities and temperatures, the waves change direction. In this case, the strange looming shapes are the result of light waves from the distant mountains that are bent downward as they traveled through different layers of air to the viewers' eyes.

Photo Details: Camera Maker: Panasonic; Camera Model: DMC-LX7; Focal Length: 17.7mm (35mm equivalent: 180mm); Aperture: ƒ/4.0; Exposure Time: 0.0006 s (1/1600); ISO equiv: 125; Software: QuickTime 7.6.6.