Think this winter is wet in Modesto area? Here are some past events that may make you think twice

John Holland
·2 min read
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Stanislaus County is plenty wet these days, but it’s far from approaching memorable storms over the past 170 or so years.

The Central Valley had truly epic floods before dams and levees were built to control the flows. Even with those public works in place, the region experienced major flooding in 1997 and stress on the system in 2017.

The Sacramento Bee just published a story that explores the history as far back as 1839. It notes how settler John Sutter consulted with Maidu and Miwok people about where to build a fort. On a hill, they advised, because the Valley is prone to massive flooding from rain and Sierra Nevada snow melt.

Most of early Sacramento was nonetheless built in the danger zone and flooded twice in the early 1850s. Then came 1862, when an estimated 4,000 people were killed as relentless rain turned the Valley into a 200-mile-long lake.

Modesto would not be founded until 1870, but flooding did contribute to the fading of nearby early settlements on the Tuolumne River.

Here are other notable weather numbers over the years, from the Modesto Irrigation District and California Department of Water Resources:

  • The wettest single day in Modesto history occurred Dec. 11, 1906, when 3.41 inches fell. The second wettest occurred Jan. 27, 2021, at 3.15 inches. The latter deluge happened amid a year that was below average overall, evidence perhaps of how climate change is messing with us.

  • Modesto’s wettest year, as measured from July 1, occurred in 1982-83 when 26.01 inches fell. An average year is 12.12 inches. The current year stood at 10.84 inches as of 2 p.m. Friday.

  • The 1997 flood lifted the Tuolumne as high as 71 feet above sea level, 16 above its banks as measured at the Ninth Street Bridge. It happened amid a series of warm storms on top of an already deep snowpack.

  • The most annual runoff in the Tuolumne watershed occurred in 2017, at 255% of average. The flow forced the opening of the spillway at Don Pedro Dam. The river ran high for several months but did not cause widespread flooding.

  • The Stanislaus River watershed also can have plenty of runoff, including a record 274% of average in 2017. But it tends to have more unused capacity than Don Pedro, allowing for gentler flows in its Valley stretch.

  • The current central Sierra snowpack was at 226% of average as of Friday, roughly halfway through the main storm season.

  • Promises can be broken: Last winter was well above average through December, but January through March were mostly dry and the year ended at 63% of average.

  • The Tuolumne was 11 feet below flood stage as of Friday, down several feet thanks to a break in the storms. That’s still too high for anyone who thinks this is a fine time for boating or swimming.