La Niña Weather System Returns, Raising Potential For Flooding In Colombia

The United States National Oceanic and Atmospheric Administration has announced that a “Double-Dip La Niña” weather pattern has developed and will extend through a second consecutive winter. La Ñiña means baby or little girl in Spanish and is the common name for a weather phenomenon defined as cooler-than-average sea surface temperatures across the central and eastern Pacific Ocean near the equator.

According to the paper: “Impact of the 2010-2011 La Niña phenomenon in Colombia, South America: The human toll of an extreme weather event,” La Ñiña is characterized by intense and abundant rainfall, increased river flow, and subsequent flooding in Colombia, though it leads to dry conditions in the Peru, Bolivia and Chile.

The same research paper in its conclusion states that Colombians are most negatively affected by the La Ñiña phenomenon are those in the lower Magdalena and Atrato river basins. The Magdalena, Colombia’s largest internal river, empties into the Caribbean along the East side of Barranquilla. The Atrato runs through the Chocó department before emptying into the Gulf of Urabá. Both river systems pass through parts of Colombia with socially vulnerable populations subject to both poverty and exploitation by rural organized crime.

Carmen Gonzalez Romero, Colombia country manager for the ACToday project told the Inter Press Service news agency: “On the one hand, heavy rains could destroy the crops of subsistence farmers. This would not only impact their access to food in the present but also in the near future threatening their basic grain reserves. On the other, large producers, associated with a guild and higher technological capacity, could also see their business endangered. This would generate a vicious cycle, laborers that work for them would lose their jobs and their income. Additionally, heavy rains could impact civil infrastructure, limiting the access to markets, which are essential for food security in the country.”

NOAA says that this La Nina is expected to last through the early spring 2022. For the upcoming winter season, which extends from December 2021 through February 2022, there is an 87% chance of La Nina. La Nina is one part of the El Nino Southern Oscillation (ENSO) cycle, which is characterized by opposing warm and cool phases of oceanic and atmospheric conditions in the tropical Pacific Ocean. Consecutive La Ninas following a transition through ENSO neutral conditions are not uncommon and can be referred to as a “double-dip.” In 2020, La Nina developed during the month of August and then dissipated in April 2021 as ENSO-neutral conditions returned.

Above image: This is what a La Nina looks like: Cooler-than-average sea surface temperatures along the equator is indicative of La Nina in the tropical Pacific Ocean in September 2021. (NOAA Climate.gov)