Science Explains Why the Snow Is Turning Rosy Red at This National Park

Teeming with nature, our country’s national parks can often offer visitors the chance to witness fascinating and perplexing natural phenomena.

Head to Montana’s Glacier National Park, for instance, and you might find yourself coming across rosy red snow with a subtly sweet scent.

The scene you’re witnessing is referred to as "watermelon snow." It occurs when a certain type of red-pigmented algae (Chalemydomonas nivalis) that contain chlorophyll combine with the snow that surrounds it to create vibrant red hues.

Joe Giersch, an entomologist at the United States Geological Survey, recently came across the phenomenon while at Grinnell Glacier, which is accessible when following the Many Glacier Road and heading on the Grinnell Glacier Trail on a ten-mile hike.

Giersch posted a photo of a puddle that was the result of melted watermelon snow, explaining how the tinted snow forms.

As Giersch and National Park representatives explain, the red pigment in the algae helps to protect its chloroplast from the sun’s radiation, allowing it to take in more heat. As the algae absorbs the sun's heat, it causes the snow around it to melt, feeding the algae with water and allowing it to continue thriving as it settles into deposits in the snow.

Over time, as rising temperatures accelerate snow melting during the summer, the algae remain concentrated in areas on the snow’s surface and appear more vibrantly. Some of the algae can even survive throughout the fall, continuing to appear pink.

The algae are also known to give off a sweet smell, hence the name watermelon snow.

That being said, NPS representatives strongly advise against any temptation to taste the sweet-smelling ice, as scientists warn that watermelon snow can cause disruption to your digestive system.

While the phenomenon is one you might expect to see closer to the summer, rising temperatures in the area show a more rapid retreat in glaciers, according to the Weather Network.