Earlier this year, news headlines began warning of a major climate event coming in the winter of 2026-27: a so-called “Super El Niño,” the likes of which hadn’t been seen in nearly a decade.

El Niño conditions, and particularly strong ones like scientists expect this winter, are linked with significant weather disruptions across the globe, including droughts, floods, heatwaves and wildfires. But like all things climate related, exactly what that could mean for you depends on where you live — and a good amount of random luck.

To help understand what we should expect, we sat down with Deputy Washington State Climatologist and UW Climate Impacts Group research scientist Karin Bumbaco, who discussed how El Niño works, what it has to do with climate change and how it might impact the Pacific Northwest this winter.

What is El Niño?

Climate.us

Scientists monitor sea surface temperatures in the eastern tropical Pacific Ocean to forecast El Niño or La Niña conditions.

El Niño is one phase of a cycle in the Pacific Ocean known as El Niño Southern Oscillation, or ENSO (pronounced “en-so”), that impacts climate patterns all over the world.

“There’s an area in the eastern equatorial Pacific Ocean called the Niño 3.4 region, where scientists assess the sea-surface temperature anomalies — what the water temperatures look like compared to normal,” Bumbaco said. “Based on those temperatures, we define whether we are in El Niño, La Niña or neutral conditions.”

El Niño conditions occur when those ocean temperatures are significantly warmer than normal, like they are this year. And because weather patterns around the world are interconnected, that warm water can affect rainfall, temperature, wind and more as far away as the United States, India and Australia.

As a result, El Niño can often bring major disruptions to fisheries, agriculture and other human activities. It is associated with flooding on the west coast of South America, forest fires in Indonesia, drought in southern Africa and India, and many other impacts.

But those weather patterns are not guaranteed.

“When we’re talking about El Niño, we’re talking about an overall seasonal forecast,” Bumbaco said. “There can always be weather events that don’t fit the expected patterns.”

In other words, El Niño loads the dice, making certain weather events more likely. But due to the randomness of the global climate, it can still produce unexpected outcomes.

What is a “Super El Niño?”

Caleb Riston

El Niño can lead to reduced mountain snowpack in the Pacific Northwest, as seen on the bare slopes of Mount Rainier.

As it turns out, scientists don’t really use the term “Super El Niño.”

“Whether it’s ‘super,’ ‘Godzilla,’ ‘monster,’ or whatever extra descriptors people use, I think they can really cause unnecessary concern,” Bumbaco said. “We typically refer to these events simply as ‘very strong’ El Niños.”

The strength of an El Niño is determined by how much warmer than normal the sea surface temperatures are. Scientists define a “very strong” El Niño as one where the temperatures are 2 degrees C or more above average.

The latest forecasts give an 81% chance that this El Niño will fall into the “very strong” range. While that strength is uncommon — there have only been a handful of such events on record, the most recent in 2015-2016 — it’s important to note that a stronger El Niño doesn’t necessarily mean more disastrous weather impacts. Instead, it simply means that the typical El Niño impacts are more likely to happen.

What does this all have to do with climate change?

The scientific jury is still out on whether climate change is making El Niño or La Niña years more frequent. What is certain, though, is that rising global temperatures are making our oceans warmer.

During La Niña years, when the surface of the Pacific Ocean is cooler than average, it tends to keep global temperatures slightly cooler as well. But when El Niño emerges, it can suddenly add a large amount of heat to the Earth’s surface.

“The last El Niño was 2023-24, and it’s no coincidence that the 2024 calendar year is the warmest year on record globally so far,” Bumbaco said. “Because we’re shifting into an El Niño pattern again this winter, it makes it that much more likely that 2027 will push those records again.”

In a sense, El Niño years reveal the true extent of the warming driven by human-caused climate change. It’s important to remember, though, that these records refer to average temperatures across the entire planet. In any one location, it is still possible to have an average or cooler-than-average year.

What does a “very strong” El Niño mean for the Pacific Northwest?

NOAA

In North America, El Niño tends to bring warmer and drier conditions to the Pacific Northwest, and more rain than usual to California and the Southwest.

“Typically during El Niño years we see warmer temperatures than normal across the Pacific Northwest, and lower precipitation than normal, particularly west of the Cascades,” Bumbaco said. “Often, because of the warmer-than-normal temperatures, we see reduced snowpack in the mountains even if there is normal precipitation, because more of it falls as rain rather than snow.”

These warm temperatures and below-average rainfall and snowpack can lead to major issues, from drought to increased wildfire risk. During past “very strong” El Niño years, though, things have looked a little different.

“In 1982-83, the strongest El Niño on record in the modern era, we had near-normal snowpack in Washington state, which was great news,” she said. “In 1997-98 and 2015-16, the next strongest El Niños, we also had near-normal snowpack.”

The problem, though, is that because these “very strong” El Niños haven’t happened very often, it’s hard to say whether they represent a real pattern or just a small sample size. As a result, it’s hard to predict whether the Pacific Northwest will get off the hook and wind up with normal snowpack this year as well.

“We’re definitely not guaranteed to see the same thing this winter,” Bumbaco said. “We have to be prepared for more typical weather impacts. And so far, our seasonal forecast models are predicting warmer and drier than normal fall and winter conditions”

How do we prepare for this El Niño, and when will it end? The water level in Lake Roosevelt, a reservoir on the Columbia River, is actively managed to both prevent flooding and retain sufficient water during drought conditions.

The Washington State Climate Office, housed within the UW College of the Environment, works closely with state officials to help government agencies, communities and businesses prepare for the impacts of El Niño events.

“At the state level, reservoir management is one of the most important ways we can prepare for an El Niño year,” Bumbaco said. “The operators can adjust to retain more water for dry periods if we think drought is likely. And because agriculture feels some of the biggest impacts from El Niño, farmers are already preparing by selecting crops that are more resistant to drought. These forecasts give everyone more time to plan.”

Luckily, we won’t be stuck with this situation for long. As a result of the complex processes that cause it, El Niño tends to burn itself out after just one winter.

“The atmospheric and ocean dynamics of El Niño patterns typically peak and then quickly return to neutral or La Niña conditions by the following winter,” Bumbaco said. “It’s much more common to have back-to-back La Niñas than El Niños.”

But as global temperatures continue to rise, we can still expect shifts between El Niño and La Niña winters. As their impacts unfold, experts like Bumbaco and others at the College of the Environment will continue working to make sure we have the information we need to prepare.

---

Story by Will Shenton