A ‘Godzilla’ El Niño could hit this winter. What that might mean for SLO County

Whether it’s El Niño, La Niña, neutral conditions, or what some call El Nothing or El Nada, meteorologists have always watched seawater temperatures across the Equatorial Pacific.

This year, many climate models predict a very strong — some say “Godzilla” — El Niño for the winter.

For people living along the Central Coast, tracking ocean temperatures is important because they hint at what kind of winter we might expect, particularly rainfall.

The term El Niño dates back centuries to Peruvian fishermen, who noticed unusually warm ocean waters arriving around Christmas. They called it “Corriente del Niño,” or “current of the Christ child.”

Today, we know that this warming is part of a much larger shift in the ocean-atmosphere system.

Under normal conditions, steady trade winds push warm water westward across the Pacific Ocean. During an El Niño, those winds weaken or reverse, and warm water spreads eastward. This shuts down the normal upwelling of cold, nutrient-rich water.

Marine ecosystems are disrupted. Fish migrate. Weather patterns across the globe begin to change.

Scientists keep a close eye on a region called Niño 3.4, a large area of the tropical Pacific along the equator, roughly halfway between South America and Hawaii. A strong El Niño happens when ocean temperatures in this region rise more than 1.5 degrees Celcius above normal for three months.

The most powerful events, like those in 1982 to 1983, 1997 to 1998, and 2015 to 2016, went over 2 degrees Celcius. They were called very strong El Niños.

The 1982 to 1983 El Niño brought 47.4 inches of rain to Cal Poly, and the 1997 to 1998 event reached 44 inches of rain, more than double the usual precipitation for the rain season (July 1 through June 30).

In contrast, the 2015 to 2016 event only brought 19.5 inches of rain to Cal Poly.

Historically, strong to very strong El Niño events increase the likelihood of wetter-than-average winters in California.

You may be wondering, how do warmer seawater temperatures far away affect California’s weather? The key is the upper-level winds.

Warmer eastern Pacific waters lead to greater evaporation. The rising vapor forms thunderstorms and releases heat, which lowers atmospheric pressure. This low-pressure area then shifts the southern branch of the polar jet stream further south.

However, as many longtime residents know, El Niño doesn’t always behave as expected, making its patterns unpredictable.

I was serving in the U. S. Navy in the Middle East during the 1982 to 1983 event, which produced huge waves that came from the southwest.

Normally, along the Central Coast, the biggest swells come out of the Gulf of Alaska and approach our shoreline from the northwest. This phenomenon creates a shadow zone in San Luis Bay where the Harford, Cal Poly and Avila Beach piers are located. The same condition also occurs at the Cayucos and San Simeon piers.

This is an important reason these piers were built in their current locations and why they have remained standing over the decades.

Those piers are usually the most sheltered along the Central Coast from damaging waves, but during strong El Niño events, storms take a more southerly route — so rough ocean waves will crash on the pier from the southwest.

This is what happened on March 1, 1983, when an El Niño-driven storm destroyed the 2,700-foot-long wooden Unocal Pier in Port San Luis. It was later replaced in 1984 with a steel-and-concrete structure, which became the Cal Poly Pier.

Reflecting on the fall of 1997, there was a sense of anticipation in the air as one of the strongest El Niños on record developed amid warm, dry weather.

I remember Pelagic red crabs, bright red creatures that resemble a cross between a lobster and a crab, washed up along our beaches, a classic sign of warmer waters.

KSBY-TV meteorologist Sharon Graves sponsored an El Niño storm preparedness workshop at the station with firefighters, police officers and emergency planners to discuss preparations for possible flooding that winter.

Yet the early season rains were modest, so by late January, many wondered if the hype had been overblown.

Then, everything changed in February.

A powerful series of storms slammed into the Central Coast. Winds at the Diablo Canyon nuclear power plant gusted to nearly 80 mph. Ocean swells reached 20 feet. Rain fell almost daily, totaling 15 inches at Cal Poly.

Rivers surged, roads washed out, and tragically, California Highway Patrol officers Rick Stovall and Britt Irvine died when their patrol car plunged into the abyss carved out by the swollen Cuyama River while responding to a report of a washout on Highway 166 in the middle of the night. Michael Tye also lost his life when his Chevrolet pickup went into the river.

During 2015 to 2016, the last very strong El Niño event produced much lower rainfall than expected.

The famous El Niño skit by the late, great comedian Chris Farley was constantly shared on social media. It was classic Chris Farley; he was dressed as a professional wrestler named El Niño. He called out to the other tropical cyclones as dark storm clouds appeared behind him.

The sounds of gale-force winds and a Weather Channel logo flashed on the TV screen.

“I am El Niño; all other tropical storms must bow before El Niño,” Farley shouted. “If any of you hurricanes are listening, step on up, because nobody can take El Niño. I challenge any of you ... tropical storms to a no-holds, barred cage match. Any time, any coast ... It’s time to pay the piper because El Niño is coming for you, and it isn’t going to be pretty.”

It’s one of my favorite skits on “Saturday Night Live.”

These events are a stark reminder that El Niño can be unpredictable, not in whether it brings impacts, but in when and how those impacts unfold.

But forecasting El Niño remains far from an exact science. Because the atmosphere behaves like a chaotic fluid, even small changes can create very different outcomes. As a result, meteorologists rely on ensemble models, which feature multiple simulations with slightly different starting points, to estimate probabilities rather than certainties.

There are also complicated factors, such as the spring barrier. At this time of year, predictions often change.

During this time, predictions are difficult because the El Niño Southern Oscillation often shifts from one phase to another in spring.

For example, a La Niña phase might fade into a neutral period before becoming an El Niño, or vice versa. As winter approaches, the models get more accurate because there’s less time for errors in the data to grow. Many climate scientists believe the best approach now is “WAS” — wait and see.

So what does all of this mean for the Central Coast?

Chances are, we could have a wetter-than-normal winter. But as always, nothing is certain.

El Niño isn’t a promise; it’s a possibility.

As the coming months unfold, we’ll keep watching the ocean’s signals, knowing they could shape the storms and stories of the season ahead.