Amazing Twilight Colors Over Northern Italy

November 23, 2017


Photographer: Matteo Curatitoli 
Summary Authors: Matteo Curatitoli; Jim Foster

The photo above shows the most beautiful sunset I've ever observed. It was taken in the foothills of the Italian Alps, near Ghemme, on the evening of October 29, 2017. The sky looked as though an artist had painted crimson-colored dunes across it. Strong winds from the north, descending over the Alps, formed lee waves and lenticular clouds, imbued with the colors of the setting Sun. The greater path length of sunlight as the sunsets reddens the sky. A profusion of dust particles in the atmosphere acts to increase the effect by scattering the Sun's waning light. Additionally, if ample water vapor is present, certain green/blue wavelengths are absorbed, so the sky looks even redder.