Argentine authorities closed tourist access to the Iguazu Falls on Monday after heavy rain linked to El Niño sent the Iguazu River surging to more than 12,000 cubic metres per second, over six times its average flow. Park officials said they expected to reopen on Tuesday, citing a gradual decline in the river's flow.
The closure was precautionary. Iguazú National Park, in Argentina's northeastern Misiones province, shut the walkways to the falls and halted ticket sales during Monday's public holiday. Staff inspected trails and infrastructure, where some small trees had fallen. Park director José María Hervás said access was closed because "it just keeps raining" and the volume of water released from dams upstream was not falling. Argentina's Naval Prefecture reported that the river rose just over two metres between Sunday and Monday at Puerto Iguazú, reaching 24.30 metres and still rising. The alert level there is 25 metres and the evacuation level 28. The National Parks Administration had forecast the flood weeks in advance.
The falls, a Unesco-recognised system of cascades about 2,700 metres wide on the border between Argentina and Brazil, are among the world's largest. Argentine officials also closed the park on its side in 2023 and 2024 because of flooding during a previous El Niño cycle.
The same weather episode has caused wider flooding in the region. Rain in the upper basin in southern Brazil has swollen the Uruguay River, which has burst its banks. In Uruguay, families were first evacuated in Salto on October 10, and in Paysandú 35 people left their homes, some now housed in army tents. A ferry service between Monte Caseros in Argentina and Bella Unión in Uruguay has been suspended. On the Argentine side, seven families were evacuated in Concordia and 31 people in Paso de los Libres, while the binational Salto Grande dam is releasing about 18,000 cubic metres per second. Last week, an atmospheric river intensified by El Niño gave Santiago, Chile, its wettest October on record and caused a mudslide in the Las Condes district.
El Niño begins in the equatorial Pacific, where shifting winds allow large amounts of heat to escape the ocean and warm the atmosphere. It typically grows through the northern hemisphere autumn, peaks around December and affects weather well into the following year. Meteorologists quoted by The Guardian say the 2026-2027 event is certain to be the biggest ever recorded, and scientists increasingly believe human-caused global heating is making such events more intense. Argentina's national weather service said last month that the country's coastal region had seen above-average rainfall similar to that during strong El Niño events. With the peak still ahead, flood risk along the region's rivers remains a concern for authorities.