When you can see the Earth reflected in the cloudsS

In icy climates, it's possible to see "cloud maps." These are literally maps of the landscape reflected on the sky, in phenomena known as ice blink and water sky.

There isn't too much to block one's view in the frozen stretches of the arctic. Unfortunately, there isn't too much to guide one, either. When navigating across a wide expanse of ice - any part of which can change depending on temperature and season - it's easy to get lost.

And so it's helpful, and poetic, when a map is written across the sky. Above is a picture of water sky. Low-lying clouds are lit up by the light shining off the ice below. When there's a sudden dip in the level of reflected light, as there is when highly-reflective ice is replaced with water, the clouds look as though they have dark streaks painted across them.

Conversely, when the clouds are dark, but suddenly light up in the distance, it's called "ice blink." The reflective ice lights up the sky and provides a beacon. Although the conditions have to be right - with clear air, just enough sun, and low-lying clouds - a map of the surrounding landscape can be literally projected across the sky.

Via Athropolis