Extreme Rainfall

Have you noticed how little rain has fallen in San Joaquin County this season? Do you remember how different it was last year? Seasonal variations have occurred for centuries, and they've become the subject of scientific analysis. In fact, an organization called the California Extreme Precipitation Symposium has been studying this subject for almost twenty years. A couple weeks ago, one of its researchers contacted me for assistance locating some important historical data. And I've written this post to ask for your help.

Flooded residential neighborhood, Stockton, Calif., 1955.

But first here's a reminder: Flooding has been an important feature of San Joaquin County for a long, long time. According to Thomas Hinkley Thompson and Albert Augustus West, History of San Joaquin County, California (1879), page 36, the most notable season since record keeping started came during the winter of 1861–1862, when almost thirty-six inches of rain fell. (Stockton currently averages about fourteen inches each year.) San Joaquin County wasn't alone that season. So severe were resulting floods throughout California's Central Valley that Leland Stanford, the state's newly elected governor, was forced to travel by rowboat to his inauguration at the Capitol in Sacramento.

Surviving evidence tells us that the winter of 1861–1862 wasn't entirely unique. Previously, similar amounts of rain had fallen in San Joaquin County during the winters of 1846–1847 and 1849–1850—and significant flooding followed. Later, much the same thing happened during the winters of 1896, 1907, 1909, 1944, 1955, and 1958. In recent years, floods of similar size are distant memories, thanks largely to controls afforded by the system of dams and waterways constructed by the state and federal governments. But a certain amount of danger still exists.

The California Extreme Precipitation Symposium is gathering data to understand these events better and to increase warning time when they occur. It focuses on science and technology, not policy issues. The Symposium already has good records for day-to-day rainfall throughout most of California from 1849 to the present, but it still needs daily figures for Stockton or San Joaquin County. The researcher who contacted me wants to find that evidence.

According to him, a wealthy Stockton merchant named J. D. Peters is known to have kept a daily record of rainfall throughout this period. I have no idea whether it still exists and, if so, where it can be found. Does anyone else? As an alternative, does anyone know of anybody else in San Joaquin County who did the same thing; whether his or her records have survived; and, if so, where to find them?

I welcome your insights, either via e-mail (leighjohnsen@sanjoaquinhistory.org) or posted as a response on this blog.

By the way, you can read more online about San Joaquin County’s experience during the Flood of 1861–1862, in Robert E. Bonta, "The Great Flood of 1861–1862," San Joaquin Historian (Jan. 1973):1–4; and John D. Newbold, "The Great California Flood of 1861–1862," San Joaquin Historian (winter 1991):1–8.

1 comment to Extreme Rainfall

  • David Stuart

    My great-great-grandfather lost everything in the great flood of 1861-62. His farm was in the Delta on Grand Island across from Rio Vista. The accounts of that flood are amazing: A sheet of floodwater in the Valley 250-300 miles long and averaging at least 20 miles in width! One quote I recall said that there was not an entire acre of dry land visible between Stockton and the Coast Range. That flood must be the archetype ARK-storm…

You must be logged in to post a comment.