AGCI Insight

Intern Showcase: Snow data comparisons

By Lauran Garcia
August 31, 2022
Two young women conduct science. A mountain is in the background. The women are surrounded by shoulder high willow bushes. One holds a tablet device, the other a soil moisture sensor.
AGCI interns Lauran (back) and Rachel (front) take soil moisture readings along a transect line using a handheld sensor at the Independence Pass site, July 2022.

About the Intern: Lauran will be graduating in 2023 with a B.A. in Sustainability Studies from Colorado Mountain College. She is passionate about natural resource management, sustainable development, and the intersection of science and society to promote an adaptive and resilient future.

This summer under the guidance of AGCI, CW3E, and YVSC mentors, Lauran conducted research on the utility of snow depth data in the Roaring Fork Valley. In addition to developing a research question and exploring scientific literature, she gained experience in GIS map development and  data access, assimilation, and visualization. She presented her final research project virtually to a scientific audience through the CW3E program. Outside of her personal project, Lauran also assisted with field data collection at the AGCI iRON soil moisture monitoring sites.

The utility of snow depth measurements in determining available water in the Colorado River headwaters of the Roaring Fork Valley

The purpose of this investigation was to determine the relationship between snow depth and snow water equivalent (SWE) in the Roaring Fork Valley both temporally across the snow season and spatially across elevation. Strong correlations between snow depth and SWE were found toward the beginning of the snow season in January, but those correlations fell considerably at the end of the accumulation period in March. Spatially, the largest differences between snow depth and SWE were found at higher elevations.  These findings are consistent with our understanding of the complex snow metamorphism occurring across the snow season that is compounded by the amount of snow at a given point on the landscape. While not a reliable metric late in the snow season, snow depth may be a reasonable proxy measurement for available water earlier in the snow season and at lower elevations in the Roaring Fork Valley where snow accumulation is less complex but still provides critical water to the watershed system.

Shared below are a few examples of some of the data analysis carried out during this project.

This graph compares SNODAS NSIDC gridded satellite data (y-axis) and snow depth in inches from the NRCS Independence Pass SNOTEL site (x-axis). Marker color and shape correspond to time of year. In some months (e.g., December) markers are closely grouped indicating a closer correlation, whereas in months like March depth and SWE are not closely correlated, and the markers are spread apart from one another.
To the left, a map shows the location of different sites in the Roaring Fork Watershed. On the right, a data table displays r^2 values for the correlation of snow water equivalent (SWE) from NSICS SNODAS to snow depth for each NRCS SNOTEL site for the time period of 2017-2022. The relationship between these two measurements is stronger in the early snow season than in later months.
Extrapolating from point measurements, this map provides a gridded visual of the relationship between snow water equivalent (SWE) as measured by NSIDC SNODAS satellite data and snow depth (as measured by in-situ NRCS stations) across the entire Roaring Fork Watershed. Lighter colors indicate a close relationship, while darker colors indicate less correlation.
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