Last of La Niña Flooding Seen in Extreme North and South of Chile, Affecting Farms in the North

Two heavy rain events simultaneously took Chile by surprise late Sunday night, March 11, 2012, that has flooded northern farms and left the southern tundra unusually wet. A torrent of rain hit the southern tip of Chile near Punta Arenas, flooding nearly 240 acres of land in the worst storm seen in 22 years. In a second, isolated area in Chile’s far north, Arica experienced two days of torrential rain that created swollen rivers; flooded homes; bridges knocked down; and, even stopped a rail line to neighboring Peru while sweeping across and drenching farms in the nearby Azapa Valley.

Figure 1. Already wet in areas of northern Chile, the heavy rain event on
March 11, 2012 just added to problems on farms in the Azapa Valley.
Water-logged soils will take time to dry out.

Within the southern town of Punta Arenas, the early flooding left 800 people displaced over a swath of land covering 240 acres. The current damage, estimate is that 4,000 people and 500 homes suffered losses. A survey of 750 homes revealed that 410 were seriously damaged and 90 were completely washed away. After 5.2 inches of rain fell in some parts of the Las Minas River Valley, a red alert was listed. Only one inch was forecast. Rain is unusual in the region. In Punta Arenas, about 2.3 inches fell. With disruption of services in the town (1,500 homes were without power), the flooding was accelerated due to the overflow from the Las Minas River that followed a 2-day rainfall. In those two days, over 25 percent of the annual average precipitation occurred. The region rarely sees any rain, but this year’s unusual rain events have waterlogged many areas in South America, perhaps due to the La Niña cycle. Much of the surrounding land hit by Sunday’s quick rain still remains flooded and unworkable by machinery. March 18, 2012, the Punta Arenas region was declared a catastrophic zone due to the barrage of flash floods. La Niña tends to provoke intense rains in Colombia, Ecuador and in the high plains of Bolivia, Peru and northwestern Argentina, it usually evokes drought in much of central Chile.

In the northern city of Arica, about 300 Chilean families had their homes flooded and officials say farms in the nearby Azapa Valley have been damaged. An unusual northern rain event prompted at the very end of this 2012 La Niña season created problems on Chilean farms and towns by causing landslides and intractable roads and railways. Heavy rains which quickly filled soil moisture holding capacities were topped by flood waters from the San José River with water flowing into the town and surrounding regions. The river rose to a depth of about 16 feet, a high point, as flood water overflowed onto surrounding land. An emergency situation was invoked around the regions of Arica, Parinacota, Tarapacá, and Magallances because of the flooding. Over 800 families were affected, including those in many of the farms in the nearby Azapa Valley.

Figure 2. Additional rain in March 2012 has flooding both the far north and far south regions
of Chile. With earlier rains in the North, intense ponding and flood conditions will exist for several weeks.

Many are calling the excess moisture in the North a “Bolivian Winter” due to the unusual rain events at the very end of the La Niña cycle. Drenched soils around the region created havoc. A mudslide from the flood blocked railroad tracks from Chile into Peru, trapping a train carrying about 300 people, who were evacuated shortly after the rains subsided enough for rescue crews to arrive on the scene. Farms in the region will take much more time for soils to dry, especially if any additional rain comes into an expected El Niño cycle as cooler weather begins.

Figure 3. Unusual, torrential rain events have recently occurred in Chile in the far

northern and southern regions. The March 11, 2012 rain storms came in at the end

of the La Nina cycle and were uncommonly intense.

This northern rainfall event brought additional problems than just water-logged soils to area farmers. The Chilean army fears that flood waters may have displaced more land mines on the border between Chile and Peru. Heavy rain earlier on February 19, 2012 dislodged about 300 anti-tank mines, forcing authorities to close the area’s main highway for several days. This main transport zone is used to move products, including agricultural supplies and other material back and forth from northern Chile into Peru. The mines were placed there in the 1970s when tensions were high between Chile and Peru. (For additional information, contact Dr. Denise McWilliams, South American crop analyst at 202-720-0107).

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