Sky Afire

September 25, 2005

Sunset8 copy

Provided and copyright by: Kevin Muenzler, Eagle Creek Observatory
Summary authors & editors: Jim Foster; Kevin Muenzler

The photo above showing a vivid sunset, as seen from Floresville, Texas (near San Antonio), was taken in the fall of 2003. This was the most impressive sunset I had seen in quite some time. Earlier in the afternoon, a passing cold front had triggered several thunderstorms, a few of which were severe. The front was basically a temperature boundary -- it was a dry front until it reached the warm, moist air nearer the Gulf of Mexico. Dust blown in from west Texas by the cold front scattered the shorter wavelengths of sunlight, but the longer, more reddened wavelengths were unaffected. At sunset, the greater path length of the sunlight through the dust laden lower atmosphere resulted in even greater scattering of the shorter wavelengths. High level clouds in the wake of the front, illuminated from the underside by the setting Sun, turned from pearl white to yellow, then to orange and finally to crimson.

Related Links: