Alpenglow's Beautiful Sunsets

The evening sky in Fairbanks has been breathtakingly beautiful the past couple of weeks. For those wondering why, here is a great explaination.

Another beautiful atmospheric optical phenomenon is the alpenglow. The late photographer Galen Rowell once wrote, "When dramatic color sorting occurs as the sunlight travels through the thickest air near the horizon, all white light vanishes and the magic hour arrives." It is easy to understand why photographers are so attracted to this phenomenon. If the sky is clear, alpenglow is observed right at sunrise and sunset, usually on the sides of mountains. It is seen only at these times because this is when the sunlight must pass through the greatest amount of atmosphere. When the sun is high in the sky, its light takes the shortest route through the atmosphere and to Earth's surface. But when the sun is close to the horizon, the light spends a far greater time in our atmosphere. This extra time in the atmosphere means extra distortion of light with shorter wavelengths, like blues and greens. The longer waves of red and orange light are not affected in the same way, and travel through the atmosphere largely undistorted. This light strikes the mountainside, and the mountain seems to glow an orangey pink. Catch it quickly, as it lasts for only a minute or two.