Coronado officials are gearing up for a Super El Niño that has already begun to impact the world’s weather and is expected to hit some coastal communities with torrential rains and damaging high tides.
According to NASA, El Niño occurs every three to seven years bringing warming sea surface temperature that affects weather patterns around the world such as increased precipitation in the southern United States, and severe drought in Australia, Indonesia, and southern Asia, also influencing tropical cyclones like hurricanes and typhoons.
It is unclear if or how the phenomenon may affect the island because meteorologists cannot predict where or when severe storms may strike.
Art Miller, research oceanographer and senior lecturer in climate sciences with UC San Diego’s Scripps Institution of Oceanography, said a Super El Niño describes the event’s magnitude in the tropical Pacific.
“There are many measures of the strength, and also the patterns, of El Niño,” added Miller. “Forecast models are in strong agreement that there will be a moderate-to-large El Niño event in 2026-27, with some of them predicting the largest ever seen in the historical record of the past 150 years. However, it does not necessarily mean that the event will have a huge impact on our own weather in the U.S. during the upcoming fall and winter.”
In anticipation, Gov. Gavin Newsom already declared a state of emergency to mobilize resources, and beachfront communities have begun preparing for potential floods while some, such as Long Beach and San Clemente, have been affected by intense waves from recent storms.
Coronado City Manager Tina Friend pointed out the island’s vulnerability during a Sept. 15 City Council meeting.
“We are, of course, very concerned with our topography and how we operate naturally being at sea level, being surrounded by water,” said Friend. “…We are working on our operational readiness.”
What is El Niño?
El Niño is anomalously warm waters in the central and eastern Pacific Ocean near the equator with its opposite being La Niña, or colder than average water temperatures in the equatorial Pacific, explains Shang-Ping Xie, professor of climate science and physical oceanography and Roger Revelle Chair in environmental science with Scripps.
“El Niño and La Niña are the result of complex interactions between the ocean and the atmosphere,” said Xie. “…Once an El Niño gets established these atmospheric and oceanic effects can reinforce each other.”
As of Oct. 8 NOAA reports: “El Niño continues to strengthen, with a strong -to-very strong El Niño likely through January-March 2027 (remaining greater than an 83% chance).”
According to NOAA, a strong El Niño will shift the Pacific jet stream, which helps determine temperature and precipitation patterns over the United States and alters the track of winter storms — leading to more precipitation over California and the southern United States.
Adam Young, coastal geomorphologist with Scripps, said El Niño conditions can generate a triple threat for coastal hazards in California.
“Increased rainfall triggers landslides; powerful waves can accelerate erosion of beaches, sea cliffs, and bluffs, and cause coastal flooding; and strong El Niño conditions can raise sea level on the California coast by 15 to 30 centimeters (6-12 inches),” said Young. “Combined, these factors increase coastal erosion and flooding during El Niño events, which can threaten public parks, beaches, critical infrastructure, highways, and homes.”
According to Scripps scientists, El Niño enhances an existing strong marine heat wave that threatens the coastal ecosystem, noting species such as tuna and sharks thrive in those conditions.
“We are preparing for this El Niño early because every Californian deserves to be safe in their home, connected to their community, and protected when severe weather comes,” said Newsom on Sept. 21.
Past El Niño events
In a memo about the 2026-27 El Niño, the California Coastal Commission reports: “While the anticipated high intensity of the El Niño event does increase the likelihood of typical El Niño impacts, there are many varieties or ‘flavors’ of El Niño that can contribute to different climate outcomes in California, and only time will tell if this winter has above or below average rains and coastal storms.”
El Niño winters in 1982-83, 1997-98, 2009-10, 2015-16, and 2023-24 experienced more frequent severe storm events with a combination of elevated water levels, higher wave energy, and shifts in wave direction, driving severe coastal erosion in many locations along the California coast, according to the memo.
The Times of San Diego reports the 2015-16 El Niño caused severe beach erosion, and closed estuaries up and down the coast such as the mouth of the Tijuana River from the ocean.
According to the Times, between October and April during that El Niño, sea levels were elevated up to 11 inches above predicted heights while erosion ranged from 6.5 feet to 10 feet above a typical winter, across San Diego-area beaches.
The rains that did come, the Times reports, were unusually intense and caused flash flooding in some areas.
Alex Tardy, a meteorologist and founder of Weather Echo, said it’s likely for west-facing beaches to experience erosion even without heavy rain.
On top of high sea levels caused by El Niño, according to Scripps, California can expect very strong king tides around Christmas time.
And currently, Coronado Council Member Amy Steward said the arrival of a Kelvin wave makes the water much higher.
“That’s been just very concerning because we’re going to have higher water, we’re going to have greater storm inundation, and that’s going to be really difficult,” said Steward.
Steward, who leads the League of California Cities’ Coastal Cities Group as vice chair of its leadership committee, said coastal inundation and storm surge are threats that are concerning to her.
According to Steward, Coronado’s South Beach is disappearing at a faster rate than North Beach as well as Grand Caribe and Tidelands.
“The beach is very, very narrow at high tide and with this higher water we’re seeing conditions that are concerning,” she said. “…Our shorelines are deteriorating. You can see it everywhere.”
El Niño preparation
Tardy, who retired from the NOAA National Weather Service after more than three decades, said historically El Niño events have brought many storms to Coronado and San Diego.
Tardy said people can expect a lot more rainy and cloudy days in addition to storms, “but don’t necessarily think that you’re going to get five storms like January 2024 just because there’s an El Niño.”
“We’re definitely concerned that we could see multiple big storms and many small storms,” said Tardy. “…These storms don’t even exist yet, but the breeding ground and the energy and the warm water and the El Niño phenomena, that’s definitely out there.”
Communities along San Diego County’s coastline are issuing warnings and taking precautions ahead of fall and winter conditions that may be exacerbated by El Niño.
This year’s efforts follow a storm on Jan. 22, 2024 that brought the heaviest rainfall in a single day in more than one hundred years across San Diego County which caused significant flooding.
The County, City of San Diego, and other coastal cities including Carlsbad, Oceanside and Del Mar, have launched online sites devoted to their preparedness efforts.
In applauding the state’s emergency declaration, San Diego Mayor Todd Gloria said:
“Here in San Diego, we are not waiting for the first major storm to arrive. City departments are already working together to prepare for potential flooding, coastal impacts, infrastructure challenges and other severe weather. The governor’s action will help strengthen that work by making additional state resources available and helping communities move more quickly on preparedness efforts.”
On Sept. 22, Del Mar declared a state of emergency in anticipation of El Niño, according to The Coast News Group.
One week later, on Sept. 30, the County of San Diego proclaimed a local emergency in preparation for heavy rain, repeated storms and significant flooding risks across the region.
A couple days later, Gloria proclaimed a local emergency in anticipation of potentially severe weather.
In a release, San Diego outlined preparations including: protective berms along beaches and the Mission Bay shoreline, conducting Emergency Operations Center responder training, and sharing emergency preparedness information through “Stay Ready, San Diego” or its public preparedness campaign for residents and businesses.
On Oct. 6, the San Diego County Board of Supervisors unanimously ratified its proclamation, amended policy and unlocked $1 million in reserves to support county efforts for severe weather impacts.
This followed a presentation by staff on the county’s plans and changes to its Emergency Operations Plan based on impacts from the January 2024 storms.
“The lessons of 2024 cannot simply be remembered,” said Supervisor Monica Montgomery Steppe, the vice chair representing District 4, who called for prioritizing drainage at flood‑prone locations. “They must be applied with precision and urgency for this upcoming Super El Niño season.”
On Oct. 6 the San Diego City Council unanimously ratified Gloria’s proclamation.
According to municipal records, Coronado was inundated with 4.25 inches of rain in a few hours in 2024.
The historic volume of water exceeded the city storm system’s capacity. Municipal officials stressed that the system did not fail, but rainfall combined with high tides impaired draining in some areas, which contributed to flooding.
“(An) atmospheric river is most concerning,” said Steward. “And if you get any kind of wind and storm surge going, it’s detrimental to our coastline.”
Steward said the city has done a great job preparing, noting the Parker Pump Station is up and running. Plans also are underway to deploy a temporary drainage system at the area of Five-Points, where multiple streets converge near the Yacht club. Run-off in that area will be pumped into Glorietta Bay.
“We are flat as a pancake but the city has taken steps to make sure that we have pumps ready, we have everything that we possibly can do,” said Steward.
Coronado’s preparedness
The Coronado City Council meeting of Oct. 6 included a discussion on emergency communications after a tsunami threat last year.
“It didn’t really result in anything happening (in Coronado) but it raised enough questions … about our mass communication systems as well as our hard infrastructure to help communicate,” said Friend.
As part of Coronado’s planning process, the police and fire departments will host multiple town halls for preparation and education, according to a city report.
On Oct. 6, Coronado selected Everbridge, an opt-in emergency and community notification platform, as its new system to replace Nixle. From Oct. 7 through April 1, the city is in a six-month transition period that includes community outreach including education and instruction at the town halls.
The city report included a hypothetical scenario of a tsunami and corresponding notifications as an incident escalates to an evacuation order.
Councilmember Carrie Downey expressed concerns about the city’s lack of an evacuation plan inferred in the scenario.
“We don’t have one,” she said. “…Maybe that should be on our list, ‘What would trigger it and where would we want people to go?’”
“We would never tell people to evacuate without some definitive instructions on direction and path,” said Fire Chief Jayson Summers.
“I’m just concerned we’re getting a little ahead of ourselves,” added Downey.
The report highlighted the city emergency notification system includes Wireless Emergency Alerts, Hi-Lo evacuation sirens on police and fire vehicles, and three Long Range Acoustic Devices. The City Council agreed to explore the acquisition of permanent audible devices.
“We’re always looking at our plans,” Friend told the council on Sept. 15. “How do we upgrade? How do we refine our response plans? How do we tailor them?”
Friend added that the mayor and City Council members are very engaged, noting an annual training for their role in a potential emergency.
The city is also planning sand bag distribution, road and intersection closures, and use of the new Parker Pump Station.
Coronado is investing $32 million to replace the existing station with a new pump station, at 8th Street and Coronado Avenue, which is responsible for collecting stormwater and sanitary sewer flows.
Friend said the Parker Pump Station is up and running with a permanent generator, but the project remains ongoing until early November.
“We’re going to have a reliable pump station online,” she added.
Brian Standing, Coronado’s division chief and emergency manager, said there is ongoing planning as the city prepares to have protocols in place by November, when they expect El Niño impacts. Standing did not respond to requests from The Coronado News for an interview about further details.
Tardy said by November it may be possible to get a sense if El Niño is affecting storms’ frequency, size and traveling direction.
“If El Niño does influence the weather pattern and produce more storms for Coronado like we’re expecting, that in turn will cause more flooding and more spread of the (sewage) contamination of Tijuana,” said Tardy.
Frank Fisher, public affairs chief of the U.S. International Boundary and Water Commission, said the commission has been busy coordinating wet-weather readiness for the El Niño winter and channel clearing ahead of the wet-weather season.
Fisher said the commission, alongside the U.S. EPA, has begun proactive coordination with regional agencies in San Diego and Tijuana to assess infrastructure integrity, including the Rodríguez Reservoir, in preparation for a potentially strong El Niño winter expected to bring heavy rain and a heightened risk of flooding from October through April.
In Tijuana, El Imparcial reports clean up efforts are underway in the Tijuana River channel by Mexican state and federal governments as El Niño increases the likelihood of rain.
“As of late September, USIBWC completed more than 1.6 miles of channel reshaping on both sides of the Tijuana River pilot channel in addition to 160 acres of mowing and vegetation clearing. Mexico completed almost 2.5 miles of improvements,” wrote Fisher. “Regarding the South Bay (International Wastewater Treatment) Plant, we completed the replacement of JB-1 earlier this year, which gives us more control over how much flow comes into the facility. We also are continuing the rehabilitation of the plant’s critical infrastructure, which will enable us to better handle sediment or trash.”
Friend said the community can expect more information moving forward and, like Steward, encourages residents to plan ahead using resources available on the city’s website at: https://www.projectcoronado.org/storm-preparedness. The city page informs Coronado residents how to prepare and stay safe during winter storms.
“El Niño’s not rain. It’s not a storm. It’s not something that you see come out of the sky,” said Tardy. “It’s an ocean warming and it’s very normal, but it’s not normal to see one this strong. And when it gets this strong, or extreme levels, it can change the atmosphere and bring us more rain, more flooding, more wind. We just don’t know exactly where that’s going to be focused even though El Niño itself is a sure thing.”
