Wayra: A new high-elevation atmospheric observatory on Mount

Project Wayra is a collaboration among scientific institutions, government agencies, and 23 private organizations to extend meteorological observations to the highest elevations of the 24 Andes. During February 2025, five automatic weather stations (AWS) were installed on 25 Mount Aconcagua (32.65°S, 70.01°W), Argentina, complementing two existing stations and 26 creating a network spanning nearly 4000 m of elevation from the valley floor to the summit 27 ridge at 6940 m. The network provides one of the highest real-time meteorological 28 observation systems in the world. The first year of observations revealed strong vertical 29 gradients and rapid atmospheric variability across the Aconcagua massif. The AWS network 30 captured multiple frontal systems, including one which was analyzed as a case study 31 demonstrating the capability of the network to observe winter storms at the top and inner 32 valleys of the high Andes. The observations show pronounced elevation-dependent snowfall 33 accumulation, strong upper-level winds, and rapid pressure and temperature changes during 34 peak storm conditions. Initial analyses also highlight the scientific and operational relevance 35 of the network, including observations of extreme solar radiation enhancement, variability in 36 physiological altitude associated with atmospheric pressure fluctuations, and applications for 37 high-elevation weather forecasting. The Wayra network provides a new platform for 38 investigating mountain meteorology, atmosphere–cryosphere interactions, water resources, 39 and mountain safety in the southern Andes.