The Last Snow on Earth May Be Pink


As glaciers thaw, one colorful group of microorganisms is thriving. (The New Yorker)

Enough with the microbes—what else causes red snow?

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit Text Set.

A hiker approaches an eerie shield of “watermelon snow” at Snowbird Glacier in the Talkeetna Mountains of Southern Alaska.
Photograph by Paxson Woelber, courtesy Wikimedia. CC-BY-SA-4.0

Discussion Ideas


  • Uh, if these microbes are green algae, why is there red snow?
    • As the snow algae get to the top of the snowpack, they turn red. The red coloring absorbs UV light. The algae need a certain amount of heat and liquid water to survive, and the increased radiation warms the organisms and melts the surrounding snow. (Pay attention to that.)






The New Yorker: Why the Last Snow on Earth May Be Red

Nat Geo: Feedbacks of Ice and Clouds

Nat Geo: What is Blood Falls?

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