Life and Times in Leschi

Early in the 20th century, the Massachusetts-based Olmsted Brothers landscape design firm, designer of New York City’s Central Park and the US Capitol grounds, was commissioned by the City of Seattle to set out a comprehensive plan for Seattle’s parks and scenic boulevards. John C. Olmsted, in surveying the terrain along the ridge from the future Frink Park and southward, saw evidence of a historic propensity for landslides along the area then known as Rainier Heights. He recommended that the entire hillside, from Frink Park southward to what is now Colman Park, become undeveloped parkland. He was concerned that continual landslides would make it difficult for the city to maintain roads and utilities.

Olmsted was certainly influenced by the large landslide of 1898. Settlement in the area was new and sparse, and the clearcut hillside had about 16 houses scattered around, plus a lumbermill on the waterfront. A vast slide from the ridgetop, between Charles and Judkins streets, swept the houses downhill and washed the mill into Lake Washington. Olmsted estimated that the land near the top of the ridge “sank from twenty to thirty feet, while the shore line was pushed out into the lake correspondingly.” He predicted that “houses will probably continue to be moved gradually on to adjoining land owned by someone else, and there will be no end to the trouble, expense, and inconvenience due to the continuation of the slide if it is allowed to become occupied by houses.”

Olmsted overreacted a bit, he conceded. In 1907 in Frink Park, he noted sudden depressions that he thought were the result of earlier landslides. After a city engineer told him that these markings were remnants from the footings of a former cable-car trestle (removed by 1900), Olmsted retracted his concern about that location.

What must not have been known to settlers at the time was the long history of slides in the area. Recent studies have confirmed a years-ago slide sequence not only in this neighborhood, but in various locations around Lake Washington and beyond. At that time, an earthquake along the Seattle Fault lifted parts of West Seattle and Bainbridge Island more than 20 feet. Dated by scientists, these events occurred in the year 923 or 924. The one in Leschi could well be the basis for the Native American cultural memory and oral history of Leschi as slide prone. (Ground movement here was attributed to the resident earth-shaking spirit known as A’yahos, which was bad-vibed away by white settlers.)

How were those ancient slides dated so closely? Researchers examined growth rings from several trees salvaged from Lake Washington; they had fallen into the lake as a result of the slide a millennium ago. Those trees were selected based on radiocarbon dating, which is accurate to within a few hundred years.

All trees of the same type in the same area have the same ring widths for a given year, correlating to weather patterns. In each case examined, the selected trees’ outer ring was fully developed, without indication of the coming year’s growth, so the trees must have died in the fall, winter, or early spring.

To more closely specify the time, a study referenced an unusual burst of solar radiation that occurred between the years 774 and 775. According that report, “this rapid, large magnitude (~10%) radiocarbon excursion … is recorded globally in tree cellulose and can therefore be used as an exact geochronological anchor point.” For any tree alive at that time, rings can be counted forward to pinpoint its season of death. This was done in the case of the trees discussed here.

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The city, for its part, did not accept Olmsted’s advice to avoid settlement on the ridge. As a result, Seattle has engaged in major efforts to stabilize the hillside. A 1935 report to the City Council said, “Earth slides have been, and always will be, a major problem in this city. … great slide [areas] extend around … the slopes leading up from Lake Washington.”

Next month: Early 20th century slides and the city’s prevention work

~Roger Lippman

The author writes monthly about Leschi history and his experiences over his 49 years in the neighborhood.