El Niño to Unleash Highest Sea Levels Ever on California Coast
El Niño Could Bring California’s Highest Sea Levels Ever Recorded
What Is El Niño? (Simple Explanation)
Imagine the Pacific Ocean like a giant bathtub. Normally, strong winds blow from east to west, pushing warm water toward Asia and allowing cold, nutrient-rich water to rise up near South America.
El Niño is when those winds weaken or even reverse. This lets a massive pool of warm water slosh back toward the Americas. It’s like the bathtub water sloshing back and forth. This warm water changes weather patterns all over the world.
Important: El Niño isn’t a storm — it’s a climate pattern that lasts for months and shifts the odds for certain types of weather.
Why Are Scientists Worried This Year?
Experts say the El Niño developing right now could be one of the strongest ever recorded.
- Ocean temperatures in the key El Niño region are warmer than any previous year on record for this time of year — even warmer than the massive 1982-83 and 1997-98 events.
- Daniel Swain, a climate scientist at UC, says: "We have not seen an El Niño event already on the trajectory that this one is on."
- The World Meteorological Organization confirms a strong El Niño is developing and will strengthen through autumn.
- UN Secretary-General António Guterres warned: "El Niño is not just on our doorstep — it is inside the house and turning up the heat."
Sea Levels Rising to Record Heights
How Does El Niño Raise Sea Levels?
Two main reasons:
- Thermal Expansion — Water expands when it warms up (like a metal bridge on a hot day). Warmer ocean = higher sea surface.
- Wind Patterns — Changing winds push water toward the California coast.
What the Data Shows
- NASA satellites already show sea levels more than half a foot higher than normal in the eastern Pacific.
- By fall and winter, scientists expect sea levels "far above the average seasonal cycle."
- Mark Merrifield (Scripps Institution of Oceanography): "We’re expecting likely the highest sea levels ever recorded on the California coast associated with this event."
Historical Peaks in San Francisco Bay
| El Niño Year | Sea Level Anomaly |
|---|---|
| 1982-83 | ~0.5 to 1 foot above average |
| 1997-98 | ~0.5 to 1 foot above average |
| 2023-24 | Notable peak observed |
| This Year | Could match or exceed past records |
Important: This El Niño rise adds on top of long-term sea level rise from human-caused climate change. It’s a "double whammy."
Coastal Flooding and Erosion Risks
The "Triple Threat" to California’s Coast
- Higher Sea Levels — Less buffer between ocean and land
- Enormously Strong Waves — El Niño generates bigger, more powerful waves
- Beaches Moving Inland — During El Niño, beaches across California move landward by ~98 feet (30 meters)
What This Means
- Waves hit closer to cliffs and infrastructure
- More flooding in low-lying areas
- Undercutting of cliffs — increased collapse risk
- Saltwater intrusion into groundwater supplies
Real-World Example (Winter 2023-24)
- Significant flooding hit Ventura, Los Angeles, and San Diego counties
- A powerful wave crashed over a seawall in Ventura, injuring eight people
Important: Merrifield warns: "That combination — high waves, high sea levels, high tides, and high rainfall will contribute to considerable coastal flooding… Flooding along the Southern California coast is likely to be a major issue for the winter season."
Heavy Rain and Storms
The "Fire Hose" Effect
El Niño can aim a "fire hose of tropical moisture" at Southern California. This happens because the shifting winds steer the storm track differently.
What Experts Predict
- High chance of a wetter-than-normal winter, especially late December through March
- Daniel Swain: "The strength of this El Niño is going to significantly shift the odds in favor of a particularly wet winter, especially in Southern California. But for an event this big, probably Northern California as well."
- But! It’s not guaranteed — the 2015-16 "super" El Niño did not bring above-average rain to SoCal.
Swain’s Personal Prep
"I’m clearing my calendar from January through March this coming year to be available if things get a little bit wild."
Marine Heat Waves and Ocean Life
Ocean Temperatures Already High
Even before El Niño fully kicks in, parts of the California coast are experiencing marine heat waves — unusually warm ocean temperatures.
El Niño Will Make It Worse
- Warmer waters suppress upwelling — the normal process where cold, nutrient-rich deep water rises to the surface
- Less upwelling = fewer nutrients = disruption of the entire food web
Impacts on Marine Life
| Species / Habitat | Impact |
|---|---|
| Bull Kelp (Northern CA) | Declined 90% since 2014 due to past heat waves |
| White Abalone (Endangered) | Depends on kelp — further threatened |
| Dungeness Crab | Fishery delayed in 2015 due to toxic algae |
| Salmon | Warmer water harms survival |
| Pelicans & Sea Lions | Poisoned by domoic acid in recent years |
Important: Nate Jaros (Aquarium of the Pacific): "Past marine heat waves caused Northern California’s bull kelp habitats to decline by 90% since 2014, which trickles down to other species."
Toxic Algae and Seafood Safety
The Domoic Acid Danger
- Warmer water → more algae (Pseudo-nitzschia) → more domoic acid
- This neurotoxin accumulates in shellfish (crab, clams, anchovies, sardines)
Health Effects in Humans
| Dose Level | Symptoms |
|---|---|
| Low | Nausea, diarrhea, illness |
| High | Short-term memory loss, seizures, fatal in rare cases |
What California Is Doing
- Domoic acid testing launching ~60 days before Dungeness crab season
- State officials anticipate higher-than-average blooms this year
- 2015 precedent: Commercial Dungeness crab season postponed due to toxic algae
What Happened in Past Strong El Niños?
| Year | Key Impacts |
|---|---|
| 1982-83 | Record sea levels, massive storms, coastal damage |
| 1997-98 | Wettest year on record for many CA locations; flooding, mudslides |
| 2015-16 | "Super" El Niño but dry in SoCal; toxic algae shut down crab fishery; marine heat wave |
| 2023-24 | Significant flooding in Ventura, LA, San Diego; wave overtopped seawall |
Important: Every El Niño is different. Strength doesn’t guarantee specific outcomes — but it loads the dice for certain risks.
What Should You Do? (Numbered Steps)
For Coastal Residents
- Know your flood zone — Check FEMA maps and local emergency info
- Prepare for power outages — Have flashlights, batteries, charged devices
- Protect property — Sandbags, clear drains, secure outdoor items
- Have an evacuation plan — Know routes and meeting spots
- Stay informed — Sign up for local emergency alerts (Nixle, AlertLA, etc.)
For Beachgoers and Boaters
- Never turn your back on the ocean — Sneaker waves are deadly
- Obey all closures and warnings — Cliff erosion makes areas unstable
- Check tide charts — High tides + high sea levels = dangerous conditions
For Seafood Consumers
- Check CDPH advisories before eating recreationally caught shellfish
- Buy from licensed sellers — Commercial fisheries are tested regularly
For Everyone
- Conserve water now — Drought may return after El Niño
- Reduce your carbon footprint — Long-term climate action reduces future risks
Summary
- A historically strong El Niño is developing — possibly the strongest on record
- Sea levels could hit all-time highs on the California coast this winter
- Triple threat: High seas + big waves + shrunken beaches = major flooding and erosion risk
- Heavy rain likely (especially Jan–Mar), but not guaranteed — 2015-16 was dry
- Ocean warming threatens marine life (kelp, crab, salmon, whales) and increases toxic algae
- State agencies are preparing — testing, monitoring, emergency planning
- You can prepare now — know your risks, have a plan, stay informed
Important: El Niño is a natural climate pattern, but its impacts are amplified by human-caused climate change. This year’s event gives us a preview of what higher sea levels and warmer oceans will look like more often in the future.
FAQ
Is El Niño caused by climate change?
No. El Niño is a natural cycle that happens every 2–7 years. However, climate change makes its impacts worse — higher baseline sea levels, warmer oceans, more intense rainfall.
Will this El Niño definitely bring heavy rain to Southern California?
Not definitely. It tilts the odds toward a wet winter (especially Jan–Mar), but the 2015-16 "super" El Niño brought below-average rain to SoCal. Think of it as loading the dice, not a guarantee.
How high could sea levels get?
Half a foot to a foot above normal in places like San Francisco Bay — on top of long-term sea level rise. Combined with high tides and big waves, this causes significant coastal flooding.
Is it safe to eat crab and shellfish this year?
Commercially sold seafood is tested and safe. Recreationally caught shellfish may be dangerous — always check California Department of Public Health (CDPH) advisories before eating.
When will El Niño peak and end?
Peak: Late fall through winter (Nov–Mar).
End: Typically spring (Apr–Jun), but impacts (like warm ocean) can linger.
This article is based on reporting from the Los Angeles Times (August 10, 2024) featuring experts from Scripps Institution of Oceanography, UCLA, California Department of Fish and Wildlife, and the Aquarium of the Pacific.