What is Watermelon Snow?

In the high mountains of the western United States, patches of snow have taken on an unusual hue—bright pink. This phenomenon, known as watermelon snow or glacier blood, is caused by blooming green algae called Chlamydomonas nivalis.

Causes of Algal Blooms

C. nivalis thrives in cold, wet environments and can be found in mountain ranges worldwide. In the drought-stricken American West, scientists believe that algal blooms may be increasing due to warmer temperatures and reduced snowpack.

Impact on Snowmelt

Algal blooms have a significant impact on snowmelt. Normally, white snow reflects sunlight, keeping the snowpack cool. However, when algae bloom and turn red, they absorb more light and heat, causing the snow around them to melt faster.

Consequences for Water Supply

In the West, snowmelt is a crucial water source for reservoirs and streams. The faster melting caused by algal blooms could lead to a diminished water supply during the hot summer months, when water is most needed.

Climate Change and Aridification

Climate change is exacerbating the drought in the western U.S., leading to unprecedented water cuts and low water levels in reservoirs. This aridification, or increasing dryness, may be contributing to the spread of algal blooms.

Monitoring and Research

Scientists are studying algal blooms to understand their impact on snowmelt and water supply. The Living Snow Project is a citizen science initiative that allows people to document algal blooms and collect samples for researchers.

DNA Sequencing

DNA sequencing is helping researchers identify the species of algae present in blooms and understand their interactions with other organisms. This knowledge can help scientists develop strategies to mitigate the effects of algal blooms.

Questions and Future Research

Many questions remain about algal blooms, including their long-term impacts on snowmelt, water resources, and aquatic ecosystems. Scientists are continuing to research these questions to enhance our understanding of this complex phenomenon.

What You Can Do

If you recreate in the mountains, you can contribute to scientific research by documenting algal blooms through The Living Snow Project app. By sharing your observations and collecting samples, you can help scientists better understand the causes and consequences of algal blooms.