Overview
- Mid‑October forecasts from NOAA as reported by CEPAL raised the chance of a very strong El Niño to over 90% and put the probability of a historically large event by December at about 75%.
- Observers record unusually high Pacific sea‑surface anomalies above +2.1°C overall and up to +3.9°C off Ecuador, Peru and northern Chile, which signal a rapidly strengthening event.
- Local impacts are already visible: the Iguazú River rose from about 18 to nearly 26 meters, forcing temporary closure of Parque Nacional Iguazú and activating flood protocols.
- Regional agencies and economic analysts say effects will be sectorized, with northern and eastern Argentina facing above‑normal rains and flood risk while some areas could see drier conditions, and CEPAL warns this will affect crop operations, infrastructure and food prices.
- Scientists explain the mechanics: eastward Kelvin waves transport subsurface heat to the surface, El Niño typically raises global air temperatures for one to two years and tends to suppress Atlantic hurricanes while increasing Pacific cyclone activity, and forecasters expect the event to peak in December–January and likely persist into early 2027.