- Airborne aircraft measured how much water is stored in Arizona’s mountain snowpack.
- The project supports more accurate runoff forecasts for Salt River Project reservoirs.
- Data will help water managers plan for spring melt and summer water deliveries.
- Flights focused on river basins upstream of Roosevelt Dam near the New Mexico border.
Tuesday, January 27, 2026 — Arizona State University and Salt River Project have announced a new effort to measure Arizona’s snowpack using advanced airborne technology
, a first for the state. The project brings together university researchers, utility scientists, and Airborne Snow Observatories, Inc., a company that specializes in mapping snow from aircraft.
Snowpack acts as Arizona’s natural water reservoir. Mountain snow slowly melts in spring and early summer, feeding rivers and reservoirs that supply cities, farms, and power generation. Knowing how much water is locked inside that snow is critical, but it has long been difficult to measure accurately in Arizona’s forested and mountainous terrain.
How the Technology Works.
For this project, airplanes are equipped with scanning light detection and ranging technology and imaging spectrometers. These instruments allow scientists to measure snow depth and determine how much water the snow contains, known as snow water equivalent. The airborne technology was originally developed at the National Aeronautics and Space Administration’s Jet Propulsion Laboratory.
The aircraft fly repeated paths across entire river basins, collecting detailed data in five to six hour flights. Depending on weather conditions, three flights are scheduled between January and March. The flights focus on areas upstream of Roosevelt Dam on the Salt River, including parts of the Upper Black River Basin near New Mexico.
Once collected, the data are rapidly processed to create detailed maps showing snow depth and water content across the landscape.
Improving Runoff Forecasts.
The new measurements are expected to improve forecasts of how much snowmelt will flow into the seven reservoirs managed by Salt River Project. Those reservoirs supply water to more than 2.5 million people in the Phoenix metropolitan area.
The data will be used to test and refine hydrologic forecast models developed by Arizona State University researchers, including Professor Enrique Vivoni of the School of Sustainable Engineering and the Built Environment.
“Mapping snow cover with these airborne technologies is a first of its kind for the state of Arizona,” Vivoni said. “We are excited about using snow maps in forested regions of the Salt River to improve runoff forecasts and train algorithms that apply artificial intelligence.”
More accurate forecasts allow reservoir operators to better plan releases, storage, and power generation as snow melts and water moves downstream.
Ground Surveys Still Matter.
Airborne measurements are only part of the effort. Salt River Project crews are also conducting snow surveys on the ground, measuring snow depth and snow water equivalent directly. These field measurements help confirm and complement the airborne data.
Together, the air and ground observations provide a more complete picture of snow conditions across the 13,000 square mile watershed, an area where precipitation and runoff can change quickly due to temperature, wind, and storms.
“This project is so critical because it will enable Salt River Project to strengthen our measurement tools and provide more accurate data as we manage the reservoirs and the 260 billion gallons of water that are delivered annually to the Valley,” said Bo Svoma, Salt River Project climate scientist and senior meteorologist.
Funding and Broader Collaboration.
The project is supported by a United States Bureau of Reclamation grant to Arizona State University’s Center for Hydrologic Innovation, along with funding from Salt River Project’s Innovation and Development Program. The Arizona Water Innovation Initiative is also providing support, bringing together researchers, students, and utility engineers to test new approaches to water management.
Airborne Snow Observatories, Inc. pioneered snow mapping technology with the National Aeronautics and Space Administration in 2013 and has applied it in several western states. The system measures snow depth, water content, and reflectivity, allowing scientists to track how snowpack changes over the season and to forecast snowmelt runoff.
Why This Matters for the Future.
As weather patterns become more variable, water managers increasingly rely on precise data rather than long-term averages. Better snowpack measurements can reduce uncertainty, improve seasonal planning, and support more reliable water supplies in a state where every drop counts.
Image via SRP’s press release.
Frequently Asked Questions
What is snow water equivalent?
Snow water equivalent is the amount of water contained in snow if it were completely melted. It is a key measure for predicting runoff.
Why measure snowpack from airplanes?
Airborne measurements can cover large, remote, and forested areas more quickly and consistently than ground surveys alone.
Where were the flights conducted?
Flights focused on river basins upstream of Roosevelt Dam on the Salt River, including the Upper Black River Basin near the Arizona New Mexico border.
How often will the flights occur?
Up to three flights are scheduled between January and March, depending on weather conditions.
How does this help water users?
More accurate snowpack data improves runoff forecasts, helping water managers plan reservoir operations and water deliveries more effectively.
