In Yosemite, 90 percent of water comes from snow, making snow the life force of the park’s varied ecosystems. Snow below 8,500 feet (70 percent of the park) is decreasing, and park scientists are seeking more information to better correlate snowmelt to water availability. This affects decisions regarding natural resources and sensitive species, such as giant sequoias, wet meadows, Yosemite toads, Pacific fishers and Sierra Nevada bighorn sheep.

In 2015, scientists collected data on stream flow, snow depth and soil moisture using state-of-the-art monitoring stations in Mariposa Grove and along Tioga Road, with the goal of building a predictive snow model that will help inform management decisions about a precious natural resource. To hone the model’s accuracy, the team worked on addressing factors such as air temperature, precipitation, and even how trees affect snow accumulation and melt.

Your contribution helped scientists continue cutting-edge research to protect the park’s — and the earth’s — natural resources.

Completed in partnership with Yosemite National Park and University of California, Merced.

Jim Roche

Park Hydrologist

Project Notes

This project develops a tool for estimating snow depth across Yosemite that will help anticipate yearly water supply, forest drought stress and wildfire potential. It will help inform the visitor regarding trail access and visit planning.