In July, a tsunami warning briefly shook up San Francisco. Although no killer waves hit our shores, the alert served as a reminder of the city’s vulnerability to sea-level rise.
By the most recent projections, Bay waters are expected to rise 10 inches by 2050. For most of the city’s shoreline, from the south end of Ocean Beach around to Islais Creek, protections for residents, businesses, and infrastructure are either planned, underway, or completed.
But one low-lying area still has no plan. There are plans to make a plan — a community meeting next week is one in a series — but there won’t be actual marching orders until at least early 2026. Even then, it could be years before workers begin grading slopes or stacking concrete blocks.
Yosemite Slough is the area in question. It’s a muddy cove just north of Candlestick Point that was once the outlet for Yosemite Creek, which springs from the ground in McLaren Park but is now mostly buried underground.
With those 10 inches of sea level rise, a big storm could flood at least a couple blocks near the slough. Those blocks are the home of warehouses, auto body shops, scrap yards, design studios, and other commercial spaces. (Perhaps the most famous is fifth-generation SF salami maker P.G. Molinari.) And the higher the rise, the larger the area at risk through the rest of this century.
There’s even more at stake. The slough is near a public housing complex, critical infrastructure, and a future Candlestick Point neighborhood (if developers fulfill long-held promises).
It’s also part of Bayview-Hunters Point, one of SF’s lowest-income neighborhoods, with a longtime Black population that has fought to improve environmental conditions for decades.
Yosemite Slough’s soil is toxic from years of industrial dumping, and rising Bay water can force contaminated ground water to the surface.
Add to that more climate peril: atmospheric rivers and other historic storms continue to take SF by surprise, exposing vulnerabilities in the combined sewer and storm water drainage system that put homes and businesses at risk.
Though climate scientists and others talk of 20-year or 100-year floods, for the folks along SF’s vulnerable shores, a perfect storm of ever-higher tides and soaking rains can come any year.
But Yosemite Slough is years behind the rest of the city. A loss of federal dollars, or outright federal hostility, could push protection plans and environmental cleanup even further into the future.
Amid these risks, city officials are moving ahead with what they can control. Yet those most directly in harm’s way — the businesses within a few blocks of Yosemite Slough — aren’t sounding the alarm. It’s not even clear they’re paying attention.
SF Planning has had little luck getting businesses to attend meetings about the project. David Eisenberg, president of analytics firm Micro-Tracers, has worked in the area for four decades. He is a community ambassador for the project and has known neighboring businesses like Molinari & Sons for years. But he says they haven’t returned his calls: “I don’t know why there’s not more concern on this issue.”
Lay of the land
The plan for Yosemite Slough officially kicked off in October 2023 with a $649,000 state grant. The first goal was to educate area business owners and residents about the impacts of flooding from storm water overflows, ground water rise, heavy rains, and sea level rise — and to work together on solutions.
An outreach team of nonprofits, plus Eisenberg as the local business rep, has held public workshops in November and May, and a walking tour in March to gather input.
Their next workshop is Sept. 16. Ahead of that, The Frisc reached out to dozens of businesses to understand their concerns about potential flooding. Only a few responded.
Walter Ricci, managing partner of real estate appraisal firm Hamilton, Ricci & Associates, owns the property at 1335 Yosemite Avenue right next to the slough. The land has been in Ricci’s family for more than 50 years. He says he’s never seen a flood in this part of the city.
Barbary Coast Garage owner Regal Davis also hasn’t seen flooding in 13 years of operation. But he says he’s prepared because his business sits three to five feet above the road.
Still, Ricci acknowledges that “100-year storms are happening sooner.” Turns out two different maps put Ricci’s business in the middle of hazard zones from such storms. A Federal Emergency Management Agency (FEMA) map shows parts of the neighborhood prone to 100-year floods. The San Francisco Public Utilities Commission (SFPUC) uses a similar metric to estimate flooding if sewer systems back up.
These are both based on historical data. Neither map takes sea level rise into account.
Ricci and other San Franciscans might remember the atmospheric rivers of late 2022 and early 2023 that inundated parts of SoMa and the Mission. There was more flooding in storms of 2024 that submerged cars near the Bayview produce market.
Flood maps don’t necessarily predict where water goes. Eisenberg’s Micro-Tracers building is just outside those lines, but he’s still concerned. If water seeps into his building, moisture and mold could contaminate the “clean room conditions” needed to make his sensitive equipment.
There’s an even larger problem at hand if flooding happens in the area: toxic sludge.
A Superfund-sized problem
Yosemite Slough’s mud is full of chemical residues from pesticides, plastics, electrical equipment, and lead — all from industrial production. The US EPA stated over a decade ago that it qualifies to be a Superfund site, though it’s not on the agency’s list of priority sites. But even if local planners hurry to design the slough’s next phase, real work on the Slough can’t start until the Hunters Point Shipyard, just to the north, gets its own cleanup.
The former shipyard, a Superfund site, is where the Navy decontaminated ships after Pacific nuclear tests, operated a radiation testing lab, and dumped radioactive materials and other toxins.
Although partially cleaned up, many parts of the shipyard still contain toxins in the soil, held in place with a cover of concrete, clay, or plastic-like material. The trouble with this solution is that groundwater can seep into the soil, push contaminants to the surface, and spread them to other areas.
Containment and cleanup gets even more complicated with rising tides. In July 2022, a scathing Civil Grand Jury report called out the city and the Navy for not considering sea level rise in its cleanup and development plans for the site. Last year, the Navy acknowledged that this was an issue.
Six months later, the EPA and Navy announced plans to clean up the final parcel — one that’s submerged in the Bay and is the nearest one to Yosemite Slough.
To avoid recontamination, the clean-up of Yosemite Slough needs to happen after the Shipyard work. According to an SF Planning spokesperson, the EPA estimates this will begin in 2028. But the Trump administration has drastically rewritten the mission of the EPA since January. When — or whether — the work actually happens is uncertain.
What SF can control is getting other pieces in place.
The future of Yosemite Slough
A walk along Yosemite Avenue toward the southern shore of the slough shows little preparation for a deluge of rain or a creeping tide. There’s some rip-rap — broken rocks that prevent erosion — and a chain-link fence with barbed wire.
The northern shore, part of Candlestick Point State Recreation Area, did get some attention in a restoration project completed in 2013. You can only access this section by foot or bike — or by flying if you’re one of the snowy egrets hanging out among the tufts of California cordgrass.
One of the goals for the Yosemite Slough project is to connect that bit of Candlestick to the rest of the SF portion of the Bay Trail, creating a contiguous path for walkers and bikers all the way to the Golden Gate Bridge and the Presidio.
Right now, there’s a range of solutions on the table. The city could build levees and add hardened protection to buildings. It could also build up the existing wetlands around the area or add vegetation that can handle higher tidal surges. There’s also a proposal to increase the slope of the shore to encourage water back into the Bay. Because businesses sit further back from the shore — unlike, say, piers along the Embarcadero — there’s more room for these kinds of native adaptations.
Just south of the slough, near Alice Griffith Apartments, trainees and staff at Literacy for Environmental Justice are planting the seeds of some of these ideas. They’re working on a project with the Port of SF to build a living shoreline of native vegetation; from their nursery, the plants are destined for Heron’s Head Park.
Patrick Marley Rump, LEJ’s director of stewardship programs, shows off trays growing sticky monkey flowers, fescue grass, and yerba buena. They’re also growing the once-extirpated California seablite and hope to bring it back to the area. Since 2022, they’ve been studying how they protect the shoreline and improve water quality at Heron’s Head.
The project will continue until 2032, and findings could inform what kinds of solutions will work in places like Yosemite Slough.
When that eventuality happens, Marley Rump says LEJ will be ready with a trained local workforce and the vegetation needed for the job. Once, he says, “there’s a better day and a shift in politics.”
Until then, winter — with its unpredictable rains and ever-rising king tides — is coming.
Correction, 9/10/25: We updated the caption of the Hunters Point Shoreline sign to clarify its location.
Correction, 9/18/25: The original version of this story misstated the name of the organization Literacy for Environmental Justice. We apologize for the error.