Very strong El Niño raises risk of extreme weather in South America
by Macarena Hermosilla · UPIJuly 8 (UPI) -- A very strong El Niño is expected to increase the risk of extreme weather across South America in the coming months, with scientists warning of heavier rainfall in some regions, severe drought in others and higher global temperatures.
El Niño has already officially developed in the Pacific Ocean and forecasters say there is a strong possibility it will intensify into a historically powerful "Super El Niño" during the second half of 2026, with significant effects across Latin America.
The U.S. National Oceanic and Atmospheric Administration and the World Meteorological Organization confirmed that ocean-atmosphere coupling has been established, with a 63% chance the event will reach "very strong" or extreme intensity between November and January.
"A 'Super El Niño' is an event with exceptionally high intensity, in which sea surface temperatures rise by more than 2 degrees Celsius," Fabiola Barrenechea, executive director of the Intergeographic Foundation, told UPI.
She said stronger ocean warming produces more intense atmospheric changes, increasing the likelihood of severe impacts.
Only four Super El Niño events have been recorded since modern observations began, during the Southern Hemisphere winters of 1997, 1998, 2015-2016.
The 2015-16 event triggered torrential rainfall and historic flooding across coastal areas of Argentina, Paraguay, Uruguay and southern Brazil, displacing more than 150,000 people and causing major agricultural losses.
At the same time, northern South America experienced severe drought that sharply reduced reservoir levels in Colombia and Venezuela, while northeastern Brazil and the Amazon saw widespread wildfires.
Extreme warming of coastal waters off Peru also triggered intense local rainfall and severely affected the country's fishing industry as anchovies migrated to colder waters.
Chile is preparing for the possible arrival of a very strong o "Super El Niño" in the coming weeks, a climate event that could bring up to 60% more rainfall than normal, increasing the risk of river flooding, flash floods and landslides in mountainous areas.
"In Chile, El Niño increases the probability of above-average rainfall across much of the country," Cristián Martínez-Villalobos, a professor at the Faculty of Engineering and Sciences at Adolfo Ibáñez University, told UPI.
He said a stronger-than-normal event could disrupt daily life and affect agriculture, transportation, infrastructure and water availability. However, he stressed that "the phenomenon by itself does not guarantee more rainfall, only a change in probabilities."
The nature and intensity of those effects vary depending on geography, local climate conditions and each area's vulnerability. Combined with ongoing global warming, a Super El Niño could also intensify heat waves and contribute to higher average temperatures across the Southern Hemisphere.
Martín Jacques, a senior researcher at Chile's Center for Climate and Resilience Research, told Deutsche Welle that El Niño is such a powerful disruption of the climate system that it produces immediate effects not only in regions bordering the tropical Pacific but also across the entire Pacific basin and globally, influencing temperatures worldwide.
"The countries historically most exposed to these changes are Ecuador and Peru," Barrenechea said.
She said both countries face a greater risk of torrential rainfall, overflowing rivers, mudslides and destructive coastal flooding because of exceptionally warm ocean waters.
Cristián Martínez-Villalobos said coastal regions are particularly vulnerable because they are generally arid and can receive extremely intense rainfall during strong El Niño events, while other regions may instead experience a higher risk of drought.
"Another important region is southeastern South America, including Uruguay, southern Brazil, Paraguay and northeastern Argentina, where El Niño typically increases the probability of above-average rainfall," he said.
"By contrast, parts of northern South America and the Amazon may face a greater risk of drier conditions, drought, heat and wildfires."
Barrenechea said the severity of the impacts depends not only on the intensity of the event, but also on how well countries are prepared through monitoring systems, early warning capabilities and identified hazard zones.
"Chile, for example, still lacks a robust monitoring system and an early warning system for meteorological events suited to its own conditions," she said.
She added that the country also needs to strengthen critical infrastructure to cope with these threats, including stormwater drainage systems, bridges and river flood defenses.