Spatio-Temporal Patterns of the 2010–2015 Extreme Hydrological Drought across the Central Andes, Argentina

Abstract

During the period 2010-2015, the semi-arid Central Andes in Argentina (CAA) experienced one of the most severe and long-lasting hydrological droughts on record. Since the snowmelt is the most important source of water, the reduced snowfall over the mountains propagated the drought signal through the streamflows in the adjacent foothills east of the Andes ranges. Motivated by the widespread impacts on the socio-economic activities in the region, this study aims to characterize the recent hydrological drought in terms of streamflow deficits. Based on streamflow data from 20 basins, we used the standardized streamflow index (SSI) to characterize hydrological droughts during the period 1971-2016. We found that the regional extent of the 2010-2015 hydrological drought was limited to the basins located north of 38 • S, with mean duration of 67 months and maximum drought severity exhibiting a heterogeneous pattern in terms of spatial distribution and time of occurrence. The drought event reached extreme conditions in 14 of the 15 basins in the CAA, being record-breaking drought in six of the basins. This condition was likely driven by a cooling in the tropical Pacific Ocean resembling La Niña conditions, which generated a decrease in snowfall over the Andes due to suppressed frontal activity.

The 2010–2015 megadrought in central Chile: impacts on regional hydroclimate and vegetation

“…2c and 5a), emphasizing the close relationship between these two variables. The SWE decrease during the MD also extended eastward of the continental divide, thus affecting the water resources of the agricultural region in westernmost Argentina (Bianchi et al, 2016;Rivera et al, 2017). Given that the accumulation and melt of the snowpack occurs within the hydrological year, we did not find any cumulative effect of the megadrought in the SWE along the Andes of central Chile.…”

“…Between 2010 and 2015 the Chilean national authorities decreed emergency conditions in 7 (out of 15) administrative regions, applying exceptional water-management measures and sending relief packages to local communities (CR2, 2015). By depleting the subtropical Andes snowpack, this drought also reduced water resources in western Argentina (Bianchi et al, 2016;Rivera et al, 2017).…”

“…The rain and snow deficit led to a concomitant decline in annual mean river flow across highly populated central Chile as well as the agricultural region of Argentina adjacent to the Andes (e.g., Rivera et al, 2017). The drought propagation through the hydrological cycle resulted in the amplification of the MDmean signal, especially in the arid part of central Chile where the normalized streamflow deficit can be twice as large as the normalized rainfall deficit.…”

Toward continental hydrologic–hydrodynamic modeling in South America

“…Previous studies showed a strong negative trend in GRACE mascon solutions in the Colorado basin (e.g. Scanlon et al, 2016) that can be associated to a decrease in snow water equivalent over the dry Central Andes (Rivera et al, 2017). Moreover, negative variations in glacier mass have been reported in southern Argentina/Chile over the Patagonia 25…”

“…Hydrol For example, a poor correlation (r < 0.2) is observed in a semiarid region covered by the Colorado basin, where snow/glacier melt has a large contribution to total runoff and corresponds to the main source of water for human activities (Rivera et al, 2017). Other locations with lower performance (NSE < 0.2) usually refer to regions strongly influenced by orography (around Andes Cordillera), which are expected due to larger uncertainties of satellite-derived precipitation in these areas (Tian and Peters-Lidard, 2010;Paiva et al, 2013).…”