NOAA says 2026-27 El Niño could be strongest on record

Federal forecasters are sounding the alarm over a developing El Niño that could become the strongest on record, with far-reaching consequences for winter weather across North America and beyond.

NOAA data now shows a greater than 90 percent chance that a very strong El Niño will take shape between October and December 2026, with a 69 percent probability that it could surpass any El Niño event recorded since 1950. Sea surface temperatures in the Niño 3.4 region were already 1.8 degrees Celsius above average during the second week of August, and most forecasting models project the event could peak above 3°C — a level Environment Canada meteorologist Bill Merryfield described as "literally off the charts".sanluisobispo+4

The three strongest El Niño events in the modern record — during the winters of 1982-83, 1997-98, and 2015-16 — peaked between 2.3 and 2.4 degrees Celsius. If current projections hold, the 2026-27 event would dwarf them all.sanluisobispo

A Reshaped Winter Across North America

OpenSnow's newly released 2026-27 winter forecast, shaped heavily by the developing super El Niño, projects above-normal snowfall across the Southwest United States, including California, Utah, and portions of Colorado. The Central Sierra — home to Mammoth Mountain — sits in the forecast's strongest signal zone for heavy snow accumulation. However, meteorologist Alan Smith cautioned that strong El Niño years also bring warm atmospheric rivers capable of pushing snow levels higher in the mountains.carsonnow+1

Northern-tier states and much of Canada face the opposite outlook: below-normal snowfall and above-average temperatures. In British Columbia, Merryfield said a milder, drier winter could produce dangerously low snowpacks, raising the risk of drought and wildfires by spring 2027.cbc+1

The polar vortex adds another variable. According to USA Today, El Niño tends to weaken the stratospheric polar vortex in mid-to-late winter, potentially triggering sudden warming events that could funnel Arctic air into the eastern United States. "This is an El Niño superimposed on top of a pretty big climate change signal," said Ben Kirtman, dean of the Rosenstiel School of Marine, Atmospheric and Earth Science at the University of Miami. "We don't have a clear understanding how that changes the teleconnections".usatoday

Global Ripple Effects

The consequences extend well beyond North America. Vietnam's National Center for Hydro-Meteorological Forecasting warned that the rainy season in the country's southern regions may end early, raising risks of drought and saltwater intrusion by early 2027. Across the tropics, the New York Times reported that parts of Panama have not seen a major storm since early May, Ethiopia's highlands are enduring one of their driest summer stretches in four decades, and India recorded its fifth-driest June since modern records began in 1901.aol+1

In the Atlantic, El Niño is already suppressing hurricane activity. NOAA's latest outlook calls for just seven to 13 named storms this season — below the historical average of about 14 — as strengthening wind shear from the Pacific pattern inhibits tropical cyclone development. "When El Niño develops, it typically becomes the primary influence on overall hurricane season activity," said Matt Rosencrans, NOAA's chief hurricane season forecaster.nytimes

For California's Central Coast, a very strong El Niño could compound coastal hazards: warmer ocean temperatures raise sea levels through thermal expansion, while powerful atmospheric river storms increase risks of flooding, debris flows, and erosion along corridors such as Highway 1 and Highway 101.sanluisobispo