If you have been hiking Yosemite’s high country recently and noticed the snow is pink, you don’t need a new eyeglass prescription.
Some snow that lasts through the summer at elevations above 9,500 feet has a slightly reddish or pink color. It’s sometimes called “watermelon snow.” Yosemite rangers explained what causes it…”The color comes from a cold-loving algae, Chlamydomonas nivalis, that thrives in freezing temperatures and liquid water, living on the snow. This algae is typically green but contains a special red pigment called a carotenoid that acts as a protective barrier, shielding the algae’s chlorophyll. Since chlorophyll is necessary for its survival, it uses this natural type of sunscreen to protect itself from too much heat and damaging UV radiation.”
If you step on the pink snow and compress it, the snow turns a deeper hue of red
Colored snow has been observed for centuries going back to Aristotle’s time. In 1818, a British expedition searching for a Northwest Passage discovered blood-red snow streaking the white cliffs of the northwest coast of Greenland, according to the London Times. When melted to a liquid, the snow was “so dark a red as to resemble red port wine.”
For years, scientists thought mineral deposits or runoff caused the coloration. The algae bloom explanation is a relatively recent development.
Frank Zappa reminded us not to eat yellow snow. The same goes for watermelon snow, even though it sounds tasty.
“Although it probably isn’t harmful to eat, we certainly don’t recommend it,” Scott Gediman, public affairs officer for Yosemite National Park, told TODAY.
Mike Moffitt is an SFGATE Digital Reporter. Email: firstname.lastname@example.org. Twitter: @Mike_at_SFGate.