If you ski or snowshoe, you have probably seen watermelon snow.
Anyone visiting the alpine areas in Whistler recently may have noticed an unusual summer phenomenon that tints the surface of the snow a pinkish-red hue. This is sometimes referred to as “watermelon snow”. While it sounds tasty we do not recommend eating it (it is not gastro-friendly for humans).
Watermelon snow has puzzled mountain climbers, explorers, and naturalists for thousands of years. Some speculated that it was caused by mineral deposits or oxidation products that were leached from rocks. We wanted to take a moment to clarify what is giving our summer snow a colour makeover.
Watermelon snow is a type of algea.
Watermelon snow is also called snow algae, pink snow, red snow, or blood snow. It is caused by Chlamydomonas nivalis, a species of green algae. This that also has a red pigment (carotenoid pigment called astaxanthin) in addition to chlorophyll. Unlike most species of fresh-water algae, it is cryophilic (cold-loving) and thrives in freezing water.
The short version is that we have an unusual green algae that loves the snow as much as we do.
Any friend of snow is a friend of ours!