In South America (SA) several documentary based climate time series exist, some of them extending back to the 16th century. Most of these records end in the 19th century, and can not be calibrated against instrumental data. Here, we used the newspaper "Los Andes" from Mendoza, Argentina, to extend documentary based indices of Mendoza precipitation and Central Andes snow depth to the late 20th century. A statistical approach to create "pseudo documentary" 20th century data was applied to prolong eight other documentary records. Increased variability of the hydrological cycle in the Central Andes and prevailing periods of wet and dry years in Mendoza suggest that the 20th century is extraordinary in the context of the last 400 years. The final set of extended documentaries explains significant portions of SA precipitation variability in large areas between 20°S and 40°S and can therefore improve the network of annually resolved precipitation proxies.