Alpenglow is the beautiful pink, orange, or reddish light that appears on mountains just after sunset or just before sunrise. The word comes from the German Alpen (Alps) and glühen (to glow), because people in the Swiss and Austrian Alps noticed this spectacular effect on their snowy peaks.

Here's what happens: after the sun drops below the horizon in the evening, most of the landscape falls into shadow. But the highest mountain peaks stay briefly illuminated, catching the sun's rays while everything below is already dark. The sunlight passes through extra atmosphere at this angle, which filters out blue light and leaves warm reds and oranges. Snow-covered peaks glow like they're lit from within, sometimes turning an intense rose or crimson color that can last for several minutes.

The same effect happens in reverse at dawn, when the peaks catch the first light before the sun rises high enough to illuminate the valleys. Photographers and mountaineers prize these moments because the colors can be so vivid and unexpected. The effect is strongest on tall mountains with snow or ice, but you can sometimes see alpenglow on any high peak if conditions are right. It's one of nature's most dramatic light shows, turning ordinary mountains into something magical.