By Amy O’Hair With research contributed by Kathleen Laderman
Toward the end of a long and severe El Niño, a disaster of epic proportions came to the north end of Foerster Street in Sunnyside. The Foerster Slide filled the streets with an avalanche of mud—up to twenty feet deep—flowing down from Mount Davidson. It destroyed five houses. Tragically, two people lost their lives.
The Red Cross declared it a major disaster. It was probably the single most well-documented event in Sunnyside history in the twentieth century, with many dozens of photographs taken by both newspapers and the Department of Public Works (DPW)—immediately after the event, and then days, weeks, even months later. I’ve assembled them all in this post, giving a fairly complete picture of the slide and its destruction.
The Foerster Slide. Sea of mud on Foerster. From about 740 Foerster St. View South. 6 Feb 1942. OpenSFHistory.org
The Foerster Slide. House at 779 Foerster slipped into street. View South. 6 Feb 1942. OpenSFHistory.org
The Foerster Slide. Sea of mud on Foerster, at about Melrose. View north. 6 Feb 1942. OpenSFHistory.org
The Foerster Slide. Sea of mud on Foerster. Houses 744 to 724 Foerster St. View South. 6 Feb 1942. OpenSFHistory.org
The onslaught of mud swept away more than lives and houses—it marked the beginning of the end for a unique enclave of early settlers in this remote corner of Sunnyside at the foot of Mount Davidson. The source of the tons of dirt that slid down to fill the streets was due to the negligence of a contractor at work on future development. In few decades, a new residential district would cover the mountain, to be called Miraloma Park. Two of the crushed houses had been standing there since the 1890s, on large rural lots with chicken houses and vegetable gardens (and even cows for some time)—the homes of early residents who preferred to live in the unpaved and unpopulated wilds on the edge of Mount Davidson.
It was a harrowing time in any case, coming just two months after the attack on Pearl Harbor and the entrance of the United States into World War II. This local disaster’s impact was perhaps muted and short-lived, as the City prepared civil defense measures against the unknown threats to come. The general sense of alarm was high; the palpable vulnerability to further attacks on the West Coast was acute. The newspapers gave instruction on how to put out incendiary bombs, should one land on your roof (use a fine spray of water) and how to best cover windows to prevent being killed by shattering glass in a bomb blast, and told people to pack what we now call a go-bag. Get to know your Air Raid Warden! (There was one such volunteer on this very block, at 732 Foerster.) 
But for the families here, the Foerster Slide was an upheaval as frightening and disruptive as anything that war might bring to their block (but never did).
The Foerster Slide. View north from just below Teresita. Piece of Negrin house on left. 7 Feb 1942. OpenSFHistory.org
The Foerster Slide. View south, with 785 Foerster in foreground, 779 in the street to the left. 7 Feb 1942. OpenSFHistory.org
The Foerster Slide. Side of 775 Foerster, slipped into street. 6 Feb 1942. San Francisco History Center, San Francisco Public Library
By Amy O’Hair [Revised with additional information December 2023.]
Here is a new map for understanding the historical path that Sunnyside’s tributary of Islais Creek once took through the neighborhood, a composite using color Sanborn maps and historical survey information from the Library of Congress, SF Dept of Public Works, and DavidRumsey.org. Additional information for areas not covered by Sanborn from Joel Pomerantz’s Seep City project for mapping our city’s old waterways.
A culvert was installed from one side of Monterey to the other at about Edna Street in the 1910s. Part of the creek was contained in a box drain in the 100 block of Flood Ave (north side) about the same time. Other manipulations took place, until the City diverted the water that would have fed it into the sewer system, during the 1920s.
My thanks to Kathleen Laderman for finding the rich vein of early detailed survey information in the historical Dept of Public Works Field Notes section of the SFDPW website, giving a priceless glimpse into the lay of the land when Islais still ran through our district.
Although this is a history blog, I offer this polemic to address a current and ongoing phenomenon; I only hope it will be history soon. The blocks of this neighborhood (and every other one in the city) are awash in the grim shades of lead, asphalt, mildew, and petro-chemical smudge, and I don’t mean the streets and sidewalks. Two-plus years of covid-era walks has made the problem impossible to ignore.
Houses are turning gray, and it’s a dreary sight. Sure, these last years have been somber, but the gray trend mushroomed well before that.
I photographed every gray house in Sunnyside*; more fell to the menace even as I thought I’d got them all. There were too many to include in this post–hundreds. I walk everywhere in the city, and it is the same in other districts. I am hardly the first to comment on this pervasive and apparently infectious color-phobia, but as it still marches on unabated, I make the case here for breaking this dull, dull spell of grimly hued houses. After several galleries of grayness, I’ll show examples of houses that buck the trend—from old-school pastels to natty new bold tones.
You may argue with my choices, but it is the agglomeration on every block of all those gray and near-gray houses that I am underlining here. It mounts up, visually—over the course of a stroll, or over the months of getting outdoors for some fresh air and a new view, only to find it is grimmer than before.
Congo Street in the Sunnyside neighborhood runs nine blocks, from Circular Avenue to Bosworth Street, from the edge of the I-280 freeway to the edge of Glen Canyon Park. It makes the ‘C’ in the short run of alphabetical street names that begins with Acadia Street on the east and ends with Hamburg Street on the west (changed to Ridgewood Avenue in 1927).
The name has been a mystery of sorts to many. A scooter messenger I once knew who liked to contemplate the city’s enigmas used to find himself pleasantly puzzled when stopped at Congo on his way out Monterey Boulevard. If you live in the neighborhood, it’s easy for the name to become part of the furniture—used but not noticed.
Unlike the picturesque set of river-themed street names in a Sacramento suburb, where ‘Congo’ sits next to ‘Klamath’ and ‘Nile,’ Sunnyside’s Congo seems without meaningful context, being next to streets named Detroit and Baden. How it came to be the choice of the Sunnyside Land Company when the district was laid out in 1891 is the story of idealized capitalist aspirations that would soon meet the realities of imperialist atrocities against indigenous peoples in the heart of Africa.
In the two decades following the naming of the street in Sunnyside, the Congo in Africa was the site of a genocide of staggering proportions. Many people have told the story; this article highlights only some of it, including a few heroes of humanitarian reform of the time who should be better known, as well as an African American poet who evoked the Congo throughout his long working life.
And the Congo has resonance in the immediate present: the recent efforts of the Black Lives Matter movement in Belgium may finally knock the villain responsible for the atrocities, King Leopold II, off his plinth. Better a century too late than never.
Blood on his hands. Many statues King Leopold II were defaced and removed during Black Lives Matter protests in Belgium, June 2020. The (UK) Independent.
One of many statues King Leopold II , being removed from its public location in Brussels, Belgium, June 2020. Reuters.
Statue of King Leopold II in Brussels, Belgium, smeared with red paint during the Black Lives Matter protests. in June 2020. Photo: John Thys. Getty Images.
The intersection of Foerster and Joost is not just a street corner in Sunnyside, it’s the stormy tale of a family torn apart by the relentless greed of one uncle, Behrend Joost, and the quiet loyalty of his nephew, Constantine Foerster, which finally gave way under the pressure of it. Joost went down in a long spiral of lawsuits, but Foerster survived and prospered, saved by taking the terrible decision to break his bond to his uncle, and stake his future in the company of men of better judgment and ethics.
Constantine E.A. Foerster was a successful and industrious corporate attorney in late nineteenth-century San Francisco. At the age of sixteen, he got his start in the city working for his uncle, a scrappy, ill-mannered hardware dealer named Behrend Joost. For many years his fortunes were deeply entwined with this uncouth entrepreneur, including as the attorney for Joost’s project to build San Francisco’s first electric streetcar system. The property speculation project called Sunnyside went along with the streetcar, and Foerster was one of several officers in the company whose names remain on the streets there.
One of Sunnyside’s shortest streets is Acadia–the ‘A’ in the brief set of alphabetized north-south streets. The name reaches deep into history, like many of the somewhat obscure choices made by the Sunnyside Land Company in 1891 when the district was laid out–such as Congo, Gennessee, and Detroit. Like those names, Acadia touches on the history of colonization and land appropriation.
Also like some of the neighborhood’s other streets, it suffered from misspelling over the years. ‘Arcadia’ was the name in directories and on maps for a time. It was a natural mistake; Arcadia, meaning a place of rural contentment, is the English version of the French word l’Acadie. The name originated in ancient Greece, referring to an isolated place there where the people lived in pastoral simplicity.
An International Atrocity
To start with, the political history: L’Acadie (anglicized to Acadia) was the name of the place where French pioneers explored and later colonists settled in eastern Canada—areas that are now called New Brunswick, Prince Edward Island, and Nova Scotia.
Investment money that funded the Sunnyside Land Company in 1890 was largely sourced from the hefty profits of some of San Francisco’s biggest late nineteenth-century breweries: Philadelphia Brewery, Albany Brewery, and United States Brewery—all overseen by the Brewer’s Protective Association. Men who were heirs to these fortunes, or wrapped up in the racket of propping up prices and selling off franchises to foreign capitalists, were among the most prominent initial investors in the Sunnyside project.
Behrend Joost, President of Sunnyside Land Company, was a notorious and irascible teetotaler, but he had no problem accepting beer-drenched money from his investors, who altogether put in one million dollars to fund the property speculation project. In return, many got their names or the places in Germany they came from on the newly laid-out streets.
Five of the original Sunnyside streets—Mangels Avenue, Spreckels Avenue, Wieland Avenue, Baden Street, and Hamburg Street—I trace directly to these men.