On a crisp spring morning, a small aircraft rises into the bright sky over southeastern Washington and parts of Oregon and Idaho. Inside, a specialized crew from the Walla Walla District, U.S. Army Corps of Engineers, peers down at the landscape. Their mission is to gather critical data about the snowpack, nature’s high-altitude water reserve, which will define the region’s rivers, farms, and communities in the seasons to come.
This annual snow flight, conducted by the district’s Water Management team in collaboration with the Idaho Natural Resources Conservation Service, U.S. Department of Agriculture, is more than just a flight, it's airborne reconnaissance with remote ground sampling to paint a detailed picture of water stored in the mountains.
“The Walla Walla District is unique in that every sub-basin is snowmelt-driven,” explained Jessika Solleder, the reservoir regulator for the Clearwater Basin with the Walla Walla District. “(Snow flights) provide us with key insights into the remaining snowpack across the basin. This directly supports critical operational decisions — managing flood risk, safely timing refill at reservoirs, supporting environmental initiatives, and regulating outflows for hydropower generation.”
Flying systematic patterns over rugged terrain, pilots and hydrologists assess snow distribution from the air and land in remote locations to collect manual measurements of snow depth, density, and water content. From the skies, subtle cues such as snowline elevation, meltwater paths and rills — reveal the snowpack’s stage of melt.
“Having an aerial view allows us to estimate snowline elevation and assess how snow is melting across various elevations,” said Solleder. “Signs of snowmelt can include meltwater ripples on the surface of the snow and the formation of rills - narrow channels formed on the surface of the snowpack due to the flow of meltwater.”
This dual approach allows the team to develop precise runoff forecasts months in advance - critical intelligence for managing the Columbia River Basin’s complex system of dams and reservoirs.
“Snow flights equip water managers with data that directly influence safety, sustainability, and quality of life in communities,” said Jon Roberts, Chief of Water Management. “It allows us to forecast runoff volumes and timing more accurately, which is essential for proactive reservoir operations, flood control, and reliable water supply.”
Beyond flood risk management, the data also benefits Pacific Northwest communities. For farmers, it supports irrigation planning. For cities and industries, it secures drinking and process water. For utilities, it forecasts hydropower capacity. And for aquatic ecosystems, it ensures fish flows remain viable.
However, snow flight operations are not without their challenges. Unpredictable mountain weather, high-altitude landings, and long field days in difficult conditions are routine.
“Flying over rugged terrain covered in snow requires highly specialized pilots,” said Solleder. “And for crew members on the ground, it’s a physically demanding job. But the strong relationship we’ve built with the USDA-NRCS team helps ensure safety and mission success every season.”
The value of this work reaches beyond technical outcomes as it embodies the Walla Walla District’s commitment to partnership, innovation, and the safety of communities. Additionally, snow survey data is shared openly with local governments, stakeholders, and tribal partners to promote collaborative decision-making and transparency.
“It’s critical for the Walla Walla District to continue investing in snowpack monitoring and forecasting,” Roberts emphasized. These flights help communities adapt to climate variability, protect infrastructure, and plan for future generations, said Roberts.
The implications for communities are significant.
Farmers depend on consistent irrigation to support crops that feed the region and the nation. Hydropower generators rely on river flows to produce clean, renewable electricity. Fish and wildlife agencies use flow forecasts to time releases that assist the migration of endangered salmon and steelhead. Cities depend on adequate water supplies for homes, schools, and businesses.
Even recreational industries, from river outfitters to lakeside resorts, benefit from the steady water levels that good planning supports.
The 2025 snow flight season marked a first for Solleder, who joined USACE full-time after graduating from Boise State University. For her, the mission is personal.
“It has always been important to me to find a career that benefits my community. At USACE, I feel I can make a direct, tangible impact on the region,” said Solleder.
As the snow begins to melt, the results of these flights become visible in every flowing river, full reservoir, and thriving ecosystem. A cornerstone of the Walla Walla District water management strategy, snow flights link technical expertise to the daily needs of PNW communities.