Glaciers and perennial snowfields are important to alpine ecosystems and regional hydrology. Quantifying volume change of a population of glaciers widely distributed over a region is difficult and expensive. We employed NASA’s novel Airborne Glacier and Ice Surface Topography Interferometer (GLISTIN) to rapidly map surface topography of alpine glaciers across the western USA. In five flight days 3289 glaciers and perennial snowfields were surveyed. Comparison with lidar over control sites showed a mean difference of +0.17 ±1.78 m at a spatial scale of 3 m. Data coverage increased and elevation uncertainty decreased with the mosaicking of multiple passes due to the complex terrain. Elevation change since the National Elevation Dataset shows a thinning (and volume loss) over the last ~56 years, averaging -0.3 ± 0.2 m and accelerating since 1980. GLISTIN can be a valuable tool for rapidly mapping ice surfaces in the alpine environment.