South America: Exceptional water deficits forecast for Brazil; surpluses in Uruguay

31 January 2017

The Big Picture
The forecast through September 2017, as seen in the 12-month map (below), shows widespread deficits in much of Brazil including a vast extent of exceptional deficits in central Brazil and along some rivers. Deficits are also forecast for Chile, Venezuela, French Guiana, and Bolivia.

Surpluses are forecast for northern Patagonia and La Pampa, Argentina; and of lesser intensity in Rio Grande do Sul, Brazil and Uruguay.

Impacts
Drought-fueled wildfires are raging across southern and central Chile in what President Michelle Bachelet is calling "the greatest forest disaster in our history." The fires have claimed the lives of three firefighters and consumed homes, farmland, livestock, and 300,000 acres of forest. The government has deployed 1,200 troops, declared a state of emergency, and appealed to other nations for help.

Intense drought coupled with poor agricultural practices are cited as the causes of wildfires in Peru that have burned through 2,668 hectares (27 square kilometers) of protected habitat, according to a report by Monitoring of the Andean Amazon Project.

Bolivia's Minister of Environment and Water has resigned amid heavy criticism of the Bolivian water crisis which resulted in severe rationing during the worst drought in 25 years. The drought prompted protests, and a state of emergency was declared after water authorities were briefly taken hostage by residents near La Paz. Reservoirs remain low, and the city's largest hospital restricted surgery to only the most urgent cases as water pressure dropped. In the country's eastern region farmers report a 50 percent loss in production - equal to 448,000 tons of soy, corn and wheat.

Forecast Breakdown
The 3-month maps (below) for the same 12-month period show the evolving conditions in greater detail.

Though the extent of water deficits in South America is expected to shrink overall from January through March, a vast expanse of exceptional deficit is forecast in central Brazil affecting southern Pará, Tocantins, Mato Grosso, Goiás, Bahia, Minas Gerais, São Paulo; as well as some western states including Rondônia, western Amazonas, and Acre. Deficits of generally lesser severity are forecast for: northern Venezuela, western French Guiana, Bolivia, Chile, and rivers in southern Argentina.

Moderate to exceptional surpluses are forecast in central Colombia, and from La Guajira in northeastern Colombia across the border into Venezuela west of Lake Maracaibo. Surpluses are also forecast for: northern Guyana, northern Brazil and Rio Grande do Sul in the south, Uruguay, and northeastern Argentina.

From April through June, overall conditions are forecast to improve. However, moderate to extreme deficits remain in the forecast for eastern Brazil. Deficits of varying severity, including exceptional, are forecast in northern Chile and along Peru’s southern coast. Primarily moderate surpluses will continue to emerge in eastern Paraguay; northeastern Argentina; Rio Grande do Sul, Brazil; and Uruguay; along with pockets of surpluses in northern Patagonia.

The forecast for the latter months – July through September – shows an increase in the extent and severity of water deficits across northern South America and eastern Brazil.

(It should be noted that forecast skill declines with longer lead times.)