Near Iguazu Falls in Argentina, the water flow in the river significantly increased, exceeding the norm by more than six times. Consequently, national park staff temporarily restricted visitor access. The river's discharge reached a level exceeding 12,000 cubic meters per second, creating a flood threat.
This sharp rise in water levels is attributed to the El Niño phenomenon and heavy rainfall. However, continuous rain and water released from dams also contributed to the increased flow. Iguazu Falls is located on the border of Argentina and Brazil and is one of the world's famous natural wonders, attracting a large number of visitors annually.
Normally, about 1,500–1,800 cubic meters of water flows through the Iguaçu River every second. But on October 12, the flow exceeded 12,000 cubic meters per second, representing an increase of more than six times. The rise in water level was caused by a combination of constant rains and water release from dams in the upper reaches of the river. This led to a risk of flooding in the area of the falls, prompting authorities to decide on closing routes to ensure public safety.
After the water level began to drop, tourists were allowed to visit the attraction again on October 13. El Niño is a natural phenomenon occurring in the Pacific Ocean where sea surface temperatures rise above normal. This affects winds and precipitation, causing increased rainfall in some regions and drought risk in others.
The World Meteorological Organization (WMO) had predicted that El Niño would strengthen on October 8, 2026. Sea surface temperatures in the mid and eastern parts of the Pacific Ocean are expected to remain about 3.7 degrees Celsius above normal from October to December, peaking around December. El Niño may also affect precipitation levels in some parts of South America.
Nevertheless, the rise in water levels in the Iguaçu River cannot be solely explained by El Niño; constant rains and dam releases played a significant role. Water levels near Iguazu Falls had also risen previously, leading to temporary closures for tourists in 2023 and 2024 when pedestrian paths were damaged. This time, authorities also closed routes out of concern for citizen safety. Reports were also made of rising water levels in other South American rivers, such as the Paraná River in October, and some residents along the Uruguay River were forced to evacuate their homes due to flooding.
There is a possibility of another rise in the water level of the Iguaçu River if heavy rains resume in the region. In such a case, officials may have to close routes again to protect tourists. Therefore, it is crucial to constantly monitor the water conditions in the river and weather conditions. After the water flow in Iguaçu increased by more than six times, tourist access was suspended. Crucially, heavy rains and dam releases played a decisive role, while El Niño may have influenced the nature of the precipitation. For this reason, timely safety measures must be taken when the river level rises.