Heat wave events and the response of glaciers in the subtropical Andes

In recent decades, an increased frequency of heat waves (HWs) has been detected along the subtropical Andes (SA); however, their impact on the cryosphere has not been assessed in detail. Here we present a multi-scale assessment with the objective of quantifying the impact of HWs on Andean glaciers located in the SA. Sub-daily observations of melt at the Universidad (34°S) and Pichillancahue (39°S) glaciers show that the daily melt rate increases by approximately 25% during HW events compared to the rest of the ablation season. At the annual scale, the relationship is complex. Using seasonal HWs climatologies derived from the ERA5 reanalysis and glacial mass balances available from the World Glacier Monitoring Service (WGMS), it was determined that there is no significant relationship between the number of HW events and the annual mass balance. However, the annual mass balance of the Echaurren Norte Glacier (33°S) showed significant positive correlations (p