What is watermelon snow and why is it best not to eat it?

Watermelon snow, also sometimes called “glacier blood”, is an amazing phenomenon of snow staining pink.

The pink hue is the result of algae living in the snow, which acquires its characteristic pink colour only in the sun. Curiously, watermelon snow is said to have a fruity flavour, but if you don’t want to get poisoned, it’s best not to try it.

The algae Chlamydomonas nivalis, which has the ability to survive at low temperatures, produces a pigment to protect against UV radiation. This pigment includes carotenoids, which are also found in carrots, tomatoes and peppers. It is these pigments that give plants, algae and bacteria their yellow, orange and, you guessed it, sometimes pink colours.