On a cloudless autumn afternoon, sunlight sparkled on the water that had quietly swallowed a busy intersection to the north of San Francisco, as the surrounding rush-hour traffic slowed to a painful crawl.
asserted
traffic → sparkle → crawl
Marin county was one of many areas up and down the California coast affected by high tides last week, as parts of the Pacific swelled with excess warmth.
asserted
parts → affect → warmth
The submerged streets stood as an early signal of California’s vulnerabilities as it braces for what could be a tumultuous winter.
uncertain
what → stand → vulnerabilities
“If you think this is bad, just wait until December,” a state worker grumbled as he directed swarms of cars past the choke point toward a sidestreet.
asserted
he → think → sidestreet
Experts have warned that a potentially historic El Niño is brewing, with the power to unleash extreme weather around the world.
asserted
Niño → warn → world
The climate phenomenon, characterized by warmer than average equatorial sea surface temperatures, is already under way, according to federal forecasters, and it is expected to strengthen through the northern hemisphere’s autumn and winter.
uncertain
it → characterize → autumn
California is poised to be in its crosshairs.
asserted
California → poise → crosshairs
Landslides, flash floods and encroaching sea levels are all on the menu – and they could all happen at once.
uncertain
they → encroach → menu
“What we’re really looking at is the compounding element,” Nick Brubaker, the chief resilience officer for the office of emergency management in Marin county said.
asserted
Brubaker → look → county
The biggest concern isn’t just rising tides.
asserted
concern → rise → ?
It’s the way everything could collide.
uncertain
everything → ’ → ?
Some areas could see supercharged storms and relentless rains.
uncertain
areas → see → storms
Others face explosive surf, strong currents and devastated marine ecosystems.
asserted
Others → face → surf
The effects of El Niño will add an additional foot of sea level rise in California on top of the 8in to 12in caused by the climate crisis there over the last century, according to Michael Anderson, a state climatologist.
uncertain
effects → add → Anderson
And in recent wildfire burn scars, including the slopes of Big Sur that burned this summer and neighborhoods devastated by the 2025 firestorm in Los Angeles, there will be higher chances of debris flows.
asserted
that → include → flows
The risks are but a taste of what’s to come as the world warms.
asserted
world → ’ → ?
Preparations are already under way at all levels of government as officials work to secure vital infrastructure, preset response resources and inform the public of the incoming hazards.
asserted
officials → work → hazards
“We are trying to make sure that people are aware that this may be one of the most significant El Niño years that we’ve seen,” Brubaker said.
uncertain
Brubaker → try → that
Preparing for a hot fall and a wet winter
California stretches across roughly 770 miles (1,240km), and its regions are likely to experience El Niño very differently.
asserted
regions → prepare → Niño
Southern California typically sees wetter winters in El Niño years, but that’s not necessarily the case further north.
asserted
that → see → years
While the stage may be set for violent weather, it’s impossible to forecast what will unfold.
uncertain
what → set → weather
“What the science supports is elevated risk,” said Dr Ariel Cohen, a meteorologist for the National Weather Service, during a recent briefing held in Los Angeles.
asserted
Cohen → support → Angeles
“A strong El Niño shifts the probabilities – it does not determine exact outcomes.”
asserted
it → shift → outcomes
With the potential for dangerous conditions already rising, emergency managers are planning for the worst.
Gavin Newsom, California’s governor, issued a state of emergency on 21 September to mobilize efforts and resources, kicking off a flurry of activity.
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Newsom → rise → activity
Adverse conditions fueled by El Niño are already taking shape.
asserted
conditions → fuel → shape
A mass of warm water known as a “Kelvin” wave is crawling up the California coastline with the ability to raise sea levels by up to a foot.
asserted
mass → know → foot
Along with coastal flooding from elevated sea levels and high tides, powerful storms swirling through the Pacific have made for an unusually busy tropical cyclone season.
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storms → swirl → season
Hawaii is still recovering from a series of deluges and strong winds that flooded roads and buildings, unleashed landslides and toppled trees.
asserted
that → recover → trees
Swathes of the southern California coastline were hammered by massive waves that damaged homes and devoured beaches.
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that → hammer → beaches
Areas already hit hard are working to recover – and build resilience.
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Areas → hit → resilience
In Long Beach, just south of Los Angeles, the seawall has been lined with large sandbags to reinforce spots where strong surf has burst through.
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surf → line → spots
In Orange county, roughly 690,000 cubic yards of sand is being pushed along the coastline.
asserted
yards → push → coastline
Workers are going door-to-door in San Diego’s flood zones to help small businesses ready their buildings.
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businesses → go → buildings
The Los Angeles county public works department has been assessing risks over the last six months, according to Mark Pestrella, its director, who said flood control systems are ready and optimized during a recent briefing.
uncertain
systems → assess → briefing
Channels and debris have been cleared from drainages, 14 dams were tested and reservoirs prepared.
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reservoirs → clear → drainages
These systems, he clarified, are designed to withstand a so-called “100-year event”, which he said had a roughly 1% chance of occurring in any given year.
asserted
he → clarify → year
But El Niño could bump those chances higher.
uncertain
Niño → bump → chances
“We are assuming it is going to rain and with El Niño we assume it is going to rain with high intensity,” Pestrella said.
asserted
Pestrella → assume → intensity
Of particular concern, he added, were the areas still in recovery from the devastating wildfires that swept across LA county in January 2025, consuming more than 16,000 structures.
asserted
that → add → structures
In Pacific Palisades and Altadena, the communities that were most intensely affected, homes and buildings are still being rebuilt.
asserted
homes → affect → Palisades
…and 27 more, not listed.
The Aporia
