Red Snow, Green Snow

It's truly spring when those last white drifts go technicolor

Microbiologist Brian Duval hates this part, so let’s just deal with the snickering up front. Yes, he studies yellow snow.

No, it’s not a murder scene. A bloom of the alga Chlamydomonas nivalis reddens the snow beside a hip-high evergreen in the Sierra Nevadas of California.