In a groundbreaking effort to measure global snowpack from space, scientists climbed to 11,500 feet in Colorado's Rockies to calibrate the NISAR satellite. The NASA-Indian Space Research Organization collaboration launched last summer aims to track water content in snow across vast regions, a capability that could transform how communities manage water resources.

The timing was critical - the team needed to measure snow depth and density exactly when the satellite passed overhead every 12 days. Using portable radar equipment dragged across mountain slopes, researchers like Emma Tyrrell of the University of Colorado recorded measurements while the satellite charted its path above. The data will help calibrate NISAR's powerful radar system, which scientists say represents the closest technology has come to measuring snow water content from space.

This calibration mission comes as the Western United States faces a record snow drought, with snowpack at 40-year lows in states like Colorado and Utah. These regions depend on snowmelt for up to 80 percent of their water supply. While NISAR isn't perfect - it struggles with dense forests and wet snow - it offers the best chance yet for wide-scale snow monitoring. With the satellite's radar planned to operate for only three years, scientists are racing to collect calibration data from locations worldwide before this window closes.