Quantifying the vulnerability of the natural storage capacity of the Andes Cordillera snowpack using a 4-km convection-permitting regional climate model

Precipitation and snowmelt from the Andes Cordillera are vital water resources for downstream communities and ecosystems, particularly in Central Chile, where agricultural water demands peak during hot, dry summers—out of sync with the winter precipitation regime. The snowpack serves as a natural reservoir, delaying water release; however, warmer temperatures are shifting precipitation patterns from snow to rain and accelerating snowmelt, potentially undermining the snowpack’snatural storage capacity. Understanding the vulnerability of this natural reservoir to climate warming is critical. In this study, we employ the Weather Research and Forecasting (WRF) model, configured for convective-permitting simulations over South America (WRF-SAAG), to analyze snowpack dynamics under current and future climate conditions. We simulate a moderate-to-high socioeconomic scenario (SSP3.7.0) over a 22-year period and compare model outputs with observations from high-elevation hydrometeorological stations in Chile and Argentina. Results show reasonable agreement in snow water equivalent (SWE) timing and magnitude, though mean monthly precipitation is overestimated by ~20%. We calculate the Snow Storage Index (Hale et al., 2023) for both historical (2000–2021) and future (2060–2080) periods, assessing its temporal and spatial variability at both grid (4 km) and catchment scales. We also analyze key snowpack characteristics, including peak SWE, duration, and melt rates, highlighting projected reductions in natural storage capacity across the Southern Andes. This research enhances our understanding of snow dynamics in a region with complex topography and varying climatic conditions. Findings are crucial for policymakers and water managers, providing essential insights for developing climate adaptation strategies in the Southern Andes foothills, an area of growing societal importance yet relatively understudied.