Science
California Snowfall Study Finds Thousands of Plastic Particles in Remote Mountains
Riverside, CA – Thousands of microscopic plastic particles are falling from the sky during Sierra Nevada snowstorms, including in remote mountain locations far from cities and roads, according to new
By Sophie Caldwell · 2026-10-29T09:22:19.578Z
Riverside, CA – Thousands of microscopic plastic particles are falling from the sky during Sierra Nevada snowstorms, including in remote mountain locations far from cities and roads, according to new research from the University of California, Riverside.
According to UC Riverside researchers, scientists measured microplastic pollution at seven snowfall collection locations, finding plastic particles at every site examined, even those accessible only by ski or chairlift.
Thousands of Plastic Particles Found in Snow
At remote locations, snowfall deposited between 270 and 3,200 plastic particles per square meter per day during peak storm conditions.
At a Mammoth Mountain ski area location, researchers recorded between 2,600 and 7,500 particles per square meter per day, roughly three times the pollution measured at remote sites.
"One site was accessed by chairlift. I had to ski to the rest of the remote sites," said lead researcher Aleksandra Karapetrova. "But no matter how far out the site, I always found microplastics there."
How Plastic Reaches Remote Mountains
Researchers explained that microscopic plastic fibers and fragments become airborne through clothing, packaging and other everyday materials.
Falling snowflakes collect suspended particles, carrying them to the ground through a process known as atmospheric scavenging.
Airflow modeling suggested that some particles may have traveled over California's Fresno and Madera counties, although exact pollution sources could not be established.
The most common materials identified included polyethylene, polypropylene and polyester/PET.
What This Means for California's Water Supply
The findings carry broader environmental significance because Sierra Nevada snowpack supplies approximately 30% of California's freshwater.
However, researchers did not determine how much microplastic pollution eventually enters drinking water or assess health effects from the particles detected.
The findings, published in Environmental Science & Technology , demonstrate how plastic pollution can travel far beyond populated areas.
"We've reached a point where plastic pollution is falling out of the sky every day, across this entire region, even when it isn't snowing," Karapetrova said.