Uncovering the mystery of how algae makes snow green, red or orange

By Nell Greenfieldboyce

Published December 25, 2025 at 5:21 PM EST

Snow isn't always white; algae can make it look green, red, or orange, and scientists are trying to understand how and why these colorful patches appear.

Nell Greenfieldboyce

Nell Greenfieldboyce is a NPR science correspondent.

See stories by Nell Greenfieldboyce

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