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Snow isn't always perfectly white. In some mountain and polar environments, microscopic algae can grow on melting snow and produce pink or reddish patches sometimes called watermelon snow.
These algae contain pigments that help protect them from intense sunlight. Darker snow can also absorb more solar energy than clean white snow, potentially increasing melting around the affected area.
Large patches can make an otherwise white landscape look unexpectedly colorful.
© Smithsonian Magazine