Snow surveys are systematic measurements of snowpack in mountainous regions. These surveys help determine the amount of water stored in snow, which is crucial for understanding water supply in rivers and reservoirs during warmer months. Conducted by agencies like the U.S. Geological Survey and National Oceanic and Atmospheric Administration, snow surveys typically involve measuring snow depth and density at various locations. The data collected is used for forecasting water availability, managing irrigation, and preparing for potential flooding events.