The melting of snow accumulated in the upper Mendoza river during winter is the main water supply for agriculture, industry and human consumption in the area. Despite its importance, there are few studies that have assessed the spatial and temporal variability of snow in this sector of the Central Andes of Argentina.

We present a technique to quantify the daily evolution of the snow cover in the basin based on the integration of scenes from Aqua and Terra MODIS sensors acquired between 2000 and 2014. This technique improves the amount of snow cover information by minimizing the impact of clouds on different sectors of the scenes, and was developed using the free programming languages R and BASH. The snow cover series obtained show significant seasonal variations with increases in winter (58% avg. coverage) and significant reductions in summer. Also, a significant inter-annual variability is observed with clear differences between dry years (e.g. 2010, with 12% average) and snowy winters (eg. 2005, 32% average). Snow cover maps also show that the sectors with greatest persistence of snow correspond with the location of glaciers in the highest, more protected and less illuminated areas in the basin. The results provide new and important information to better understand the distribution and variability of snow cover in this sector of the Andes. They can serve as the basis for multiple applications including the hydrological modeling of the Mendoza river, contributing to improve the management of the water resources.