What we previously think snow looks like is changing with the pink snow that turned orange in America. Ever since the formation of planet Earth and the emergence of the first species, snow-capped mountains have stood as steady markers of the seasons – clean, white, and predictable – at times. In winter, they store water. In spring and summer, they slowly release it, feeding rivers, reservoirs, and entire regions downstream. From the Rockies to the Alps, these frozen peaks have been essential to life in nearby valleys and faraway cities alike.
Snow is less predictable now
That balance, however, is becoming less reliable. With global temperatures rising, mountain snowpacks are melting both earlier in the season and at a faster pace. What used to remain frozen for months can now disappear within weeks. As a result, the timing of runoff is shifting, putting stress on reservoirs and forcing entire water systems to adjust. These trends have long been predicted by climate models — and now, they’re playing out in real time.
At the same time, scientists are paying closer attention to the surface of snow itself. Subtle changes in color, texture, and melt rate are now being studied as signals — not just of warming, but of how snow interacts with sunlight, air quality, and microbial life. These signs can be easy to miss. But in the high elevations of North America, something new has caught the eye — and it’s not just researchers who are starting to worry.
Utah locals spot pink snow changing color
This summer, people in Utah have been noticing something unusual with the snow. Some patches were colored with red and pink hues. The eye-catching sight, commonly known as “watermelon snow,” isn’t just a rare trick of the light — it’s a natural phenomenon seen in mountain regions around the world.
Despite the bright, sometimes reddish colors, the cause is microscopic. Scientists point to a green algae species called “Chlamydomonas nivalis”, which is known to grow in cold, snowy environments. According to Scott Hotaling, a watershed sciences professor at Utah State University, this algae is capable of turning snow a range of colors — red being the most common, but sometimes purple, green, or even orange depending on the species and conditions.
The reason for the change of colors
This particular algae usually exists in a dormant state, almost like a cyst, but during the spring — when melting snow creates more available water and nutrients — the algae becomes active, what causes the pink snow effect. Hotaling explained in an interview with CNN that once conditions are right, the algae develops tiny flagella that allow it to move through the snowpack to the surface, where it can bloom under the sun.
The bloom is part of its reproductive cycle. As it grows, the algae produces a pigment that darkens its cells. This pigment plays a protective role, acting like sunscreen by shielding the algae from the sun’s ultraviolet radiation. Hotaling made an analogy to human skin tones, noting that just like fair-skinned people are more sensitive to sunlight and need more protection, so too does the algae benefit from additional pigmentation.
Other states can also experience the pink snow
Interestingly, the pigment doesn’t just protect the algae. As it absorbs sunlight, it warms the surrounding pink snow, helping to melt more of the surrounding ice. While the phenomenon itself isn’t new, it’s been more visible this year thanks to an unusually heavy snow season across parts of the western U.S. CNN’s senior meteorologist Brandon Miller noted that states like Utah, Nevada, and California had been dealing with drought and low snowpack in recent years. But in 2024, the snowfall in some areas left pink snow holding up well into the summer.