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What is watermelon snow? © Alamy
© Alamy

What is watermelon snow?

Published: 06th May, 2022 at 18:00
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It's also known as blood snow, pink snow, or red snow.

Otherwise known as glacier blood, watermelon snow is found worldwide in mountains and polar regions. The pink-red snow has a faintly fruity smell but is reported to have laxative effects if eaten.


The watermelon colour comes from freshwater green algae called Chlamydomonas nivalis. In summer, the algae produce a red pigment to protect themselves from the Sun’s intense rays. This pigment belongs to a large group of carotenoid substances, many of which are found in brightly coloured fruits and vegetables such as tomatoes and carrots.

Unfortunately, the pigment reduces snow’s ability to reflect heat, leading to faster melting rates.

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Asked by: Connor Sykes


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Dr Emma Davies is a science writer and editor with a PhD in food chemistry from the University of Leeds. She writes about all aspects of chemistry, from food and the environment to toxicology and regulatory science.


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