NASA deploys UAVSAR flights to map snowmelt and refine water resource forecasting

NASA deploys UAVSAR flights to map snowmelt and refine water resource forecasting
by Clarence Oxford
Los Angeles CA (SPX) Apr 28, 2025

RIn a mission to deepen understanding of one of Earth's most vital resources, NASA's C-20A aircraft completed seven specialized research flights in March, gathering critical data on snowmelt processes and freshwater availability. Equipped with the Uninhabited Aerial Vehicle Synthetic Aperture Radar (UAVSAR), the aircraft collected precise measurements of seasonal snow cover to estimate the freshwater volume locked within.

"Seasonal snow is a critical resource for drinking water, power generation, supporting multi-billion dollar agricultural and recreation industries," said Starr Ginn, C-20A project manager at NASA's Armstrong Flight Research Center in Edwards, California. "Consequently, understanding the distribution of seasonal snow storage and subsequent runoff is essential."

Dubbed the Dense UAVSAR Snow Time (DUST) mission, the project mapped snow accumulation patterns across California's Sierra Nevada range and the Rocky Mountains in Idaho. These observations enable scientists to better quantify how much water is stored in seasonal snowpacks.

"Until recently, defining the best method for accurately measuring snow water equivalent (SWE) - or how much and when fresh water is converted from snow - has been a challenge," said Shadi Oveisgharan, principal investigator of DUST and a scientist at NASA's Jet Propulsion Laboratory in Southern California. "The UAVSAR has been shown to be a good instrument to retrieve SWE data."

Shifting weather patterns and evolving snow properties in the western United States have challenged traditional assumptions about snowpack behavior and runoff predictions. The DUST mission aims to advance understanding of these dynamics, providing improved estimates of the timing and volume of snowmelt conversions into freshwater.

"We are trying to find the optimum window during which to retrieve snow data," Oveisgharan said. "This estimation will help us better estimate available fresh snow and manage our reservoirs better."

The mission's improved snow measurement precision owes much to the advanced flight capabilities of the C-20A. Its Platform Precision Autopilot (PPA) allows researchers to maintain exact flight routes, speeds, and altitudes, enhancing the quality of terrain data collected by UAVSAR.

"Imagine the rows made on grass by a lawn mower," said Joe Piotrowski Jr., operations engineer for NASA Armstrong's airborne science program. "The PPA system enables the C-20A to make those paths while measuring terrain changes down to the diameter of a centimeter."

Research Report:Snowfall Replenishes Groundwater Loss in the Great Basin of the Western United States, but Cannot Compensate for Increasing Aridification