What a record el nIÑO could Mean for us

Federal forecasters are now near-certain that this winter will bring a very strong El Niño, possibly the strongest ever recorded. For those of us in Novato, the practical translation is straightforward: a higher-than-usual chance of heavy storms between October and March, a real possibility of record-high water in San Pablo Bay, and a good chance that Highway 37 closes for days at a time when the two coincide.

This is not a forecast of disaster. El Niño tilts odds; it does not guarantee outcomes. So, what should we be ready for this winter?

What are forecasters actually predicting?

NOAA's Climate Prediction Center has El Niño at Advisory status, with a greater than 90 percent chance of a very strong event during fall and winter 2026-27. The agency puts the odds at 69 percent that this event exceeds every El Niño in the record going back to 1950. NOAA Climate Prediction CenterABC7 San Francisco

What that means locally is less certain than the headlines suggest. Climate scientist Daniel Swain has been explicit that nobody can predict a major California flood event this far out. The 2015-16 El Niño was very strong in the Pacific and delivered a famously dry Northern California. What a strong El Niño reliably does is raise the ceiling on how bad an individual storm can get. Weather West

The sea level piece is more concrete. El Niño temporarily lifts the ocean surface by roughly six inches, layered on top of about eight inches of rise since the 1880s. Stack peak king tides on that, and researchers at the Scripps Institution of Oceanography told a town hall hosted by Senator Mike McGuire that they expect likely the highest sea levels ever recorded on the California coast in connection with this event. Marincounty

Marin already got two previews this year. King tides and storm surge over New Year's weekend closed parts of Highway 101, flooded homes and vehicles, and left whole neighborhoods islanded. Congressman Jared Huffman toured the damage in Larkspur and Corte Madera and said the county seemed to have been caught off guard by the scale of it. Then in June, the Bay Area recorded its highest summer tides ever measured, peaking at 1.97 feet above normal, with parts of Marin underwater. houseKQED

Why does Highway 37 matter so much to Novato?

Because it is the road, and it sits at sea level.

Highway 37 runs 21 miles across the San Pablo Baylands from the 101 junction here in Novato east to Vallejo, and it carries roughly 40,000 vehicles a day. It was built on land that was bay before settlers diked and drained it. When a high tide meets a storm, water does not rise toward the road. It arrives on it.

Marin County Public Works has long flagged 6.3 feet at the San Francisco tide gauge as the level where significant rainfall starts producing flooding on low-lying county roads. In January 2017, a levee near the highway failed after heavy rain, roughly 650 million gallons filled the fields alongside it, water came over the westbound lanes, and Marin County declared a state of emergency. Emergency repairs alone ran past $1 million. In January 2023, Caltrans closed the highway between 101 and Atherton Avenue after Novato Creek overtopped a levee, then placed six portable pumps in a westbound lane and spent four days pumping the road dry. CBS News + 2

So the question for our neighborhood is not only whether our own street floods. It is that a multi-day closure of 37 pushes tens of thousands of commuters onto 101 and the Richmond Bridge, and reroutes anyone here who works, has family, or gets medical care to the east.

What is Marin County doing before winter?

The county presented its readiness strategy to the Board of Supervisors on August 18. The plan includes evaluating temporary flood mitigation measures well before the season starts, a series of emergency exercises involving county departments, cities, first responders and utilities, and expanded work with the National Weather Service on local forecasting and public communication. Marincounty

Closer to home, the Marin County Flood Control District began sediment removal on Novato Creek, Warner Creek and Arroyo Avichi in June to maintain the creeks' designed flood-conveyance capacity. That is routine maintenance, but it is the specific work that determines how much water our creek can carry before it goes somewhere else. Marincounty

Regionally, the AQPI storm radar network is now operational, including a C-band unit on Mount Barnabe in Marin. It combines five short-range radars filling gaps over flood-prone areas with one long-range radar watching atmospheric rivers approach from the ocean, and it is the reason local agencies should get better warning this winter than they had last January. Scripps Institution of Oceanography

The county's own message has been blunt. Office of Emergency Management director Steven Torrence put it this way: preparedness is a shared and essential responsibility, and residents should not wait for the first atmospheric river to think about it. Marincounty

Did the Highway 37 funding vote help Novato?

Not this stretch, and not this winter.

On August 21, the California Transportation Commission unanimously approved nearly $100 million for the corridor. That is $32 million for operational improvements at the Highway 121 intersection plus roughly $63 million toward Phase 1 of the Sears Point to Mare Island project. The money repairs the Tolay Creek Bridge and converts the shoulders of the bottlenecked 10-mile section into additional lanes, some of them tolled. Real progress on congestion, and worth having. But all of it is east of us. San Francisco Chronicle + 2

The Marin segment is a separate project. The Novato Creek bridge is slated to be rebuilt at the full future elevation, which would make it the first piece of the entire 21-mile corridor constructed to final height. That is the piece that matters for the flooding we actually see. It was not what was funded last week.

The long-term vision is an elevated four-lane causeway skimming above restored wetlands, and there is genuine disagreement about it. The full rebuild is now forecast at roughly $11 billion over more than twenty years. Rep. Huffman has criticized the near-term lane additions as a sunk cost, given that the state ultimately intends to tear the structure down. Fraser Shilling, who directs UC Davis's Road Ecology Center, has argued that a bridge, a tunnel, or moving the road inland would be smarter than the causeway design. San Francisco ChronicleYahoo!

Reasonable people are still arguing about the fix. None of it helps us for this coming winter.

What should each household do in the next six weeks?

Most of this costs nothing and takes an afternoon.

Sign up for AlertMarin. It is the county's primary emergency alerting system and it sends location-specific messages for coastal, creek and roadway flooding. Sign up at marin.sircom.org/subscribe, and register every phone in the house, not just one.

Clear your drainage. Gutters, downspouts, driveway drains, and the culvert or ditch at your property line. Compost the leaves rather than sweeping them into the street gutter, where they clog the system for everyone downhill.

Bookmark the road tools. Caltrans QuickMap at quickmap.dot.ca.gov for live lane conditions, and 511.org for traffic and transit. ReadyMarin at readymarin.marincounty.gov has the preparedness checklists. During storms, the county's Emergency Portal at emergency.marincounty.gov carries updates and sandbag locations.

What can we do together that we cannot do alone?

This is the part that only works if we do it before we need it.

Build the contact list now. A group thread that already exists on a normal Tuesday is worth more than any plan drafted during a power outage. Include landlines and a backup contact for anyone who travels.

Map who has what. Generators, chainsaws, four-wheel drive, a truck bed, medical training, ham radio.

Know who would need help. Neighbors who live alone, who do not drive, who have mobility limitations, who have medical equipment that needs power. Someone specific should be checking on each of them, and that neighbor should know who it is.

Compare notes on routes. If 37 closes for three days, who here is affected, and who has the flexibility to carpool, cover a school run, or pick something up on the far side of the bay?

The short version

NOAA gives better than 90 percent odds of a very strong El Niño this fall and winter, with a 69 percent chance it exceeds every event since 1950. The likely local consequences are heavy atmospheric river storms between October and March, record or near-record high water in San Pablo Bay when El Niño elevation stacks on peak king tides, and multi-day closures of Highway 37 where it crosses the baylands near Novato Creek. Marin County has staged its winter readiness plan, the Flood Control District cleared Novato Creek sediment in June, and the regional AQPI storm radar is now running. The nearly $100 million the state approved on August 21 goes to the Sonoma and Solano portions of the corridor, not the Marin segment that floods here, and the permanent causeway is a roughly $11 billion project more than twenty years out. Households should sign up for AlertMarin, look into flood insurance while the 30-day waiting period still leaves time, clear drainage, and test pumps and generators. As a neighborhood, the highest-value work is the contact list, the resource map, and a list of neighbors who would need help.

Sources

NOAA Climate Prediction Center, ENSO Diagnostic Discussion (August 13, 2026) · County of Marin, "County Strategizes for Potential El Niño Season" (August 17, 2026) · Marin County Flood Control District, Novato Creek Sediment Removal Project (June 2026) · Marin County Public Works, tide-related flooding advisories · KQED, "San Francisco and Marin Face Flooding Amid Highest Summer Tide on Record" · SFGate, "Climate scientists warn El Niño may bring tallest-ever seas to California" · Rep. Jared Huffman, "Rep. Huffman tours flooded Marin" (January 2026) · Caltrans District 4, SR-37 closure and reopening releases (January 2023) · CBS Bay Area, Marin County state of emergency coverage (January 2017) · Press Democrat, "Nearly $100 million in funding approved for Highway 37 improvements" (August 21, 2026) · San Francisco Chronicle, Highway 37 funding coverage (August 2026) · Scripps Institution of Oceanography, AQPI announcement (March 2026) · Weather West (Daniel Swain), El Niño special update (June 2026)