Melt ponds, ice and glaciers

Melt ponds form when a piece of ice breaks off a retreating glacier and sinks into the ground. The colours of the lake indicate the amount of sediment or depth: the deeper or clearer the water, the bluer the lake.
Iceland is also home to ice caves. Glaciers, which are retreating all over the world, also play with palettes of blue, but also brown and grey.