High in the Peruvian Andes, Oliver Wigmore has helped open a new scientific frontier: The earth scientist has flown a data-collecting drone to nearly 5000 meters, the highest such flight ever reported in the scientific literature, he and colleague Bryan Mark report this week in The Cyrosphere. To understand how tropical glaciers are responding to climate change, Wigmore, now at the University of Colorado in Boulder, custom-built an ultralight six-rotor hexacopter designed to reach 6000 meters. Equipped with large propellers and high-speed motors, it can cope with the thin air, strong winds, and harsh conditions found at high altitudes—something that your typical out-of-the-box kit simply can’t do. In the summers of 2014 and 2015, when Wigmore was at the Ohio State University in Columbus, he sent the drone soaring to 4900 meters above the steep valleys of the snowy Cordillera Blanca in Peru, where some 700 glaciers are a key source of water for the valleys below. The hexacopter’s camera collects images that are far more detailed than those captured by satellites, allowing researchers to create three-dimenstional models of how ice conditions are changing. The drones are also cheaper to use than traditional aircraft, and can reach areas that are inaccessible by foot. Wigmore, who is now using his drones to study snow, water and vegetation in the Rocky Mountains of North America, believes the craft will help scientists better understand how global warming is playing out in hard-to-reach regions. And he predicts his altitude record won’t last long: He and other drone-equipped researchers are already pushing higher in their quest to better understand the changing Earth.