Sonoma County has declared a local emergency ahead of this winter's rainy season, as county leaders brace for what forecasters say could be the strongest El Niño pattern in more than 70 years. The declaration is meant to give the county a head start on staffing, training, and flood preparations before December's rains arrive.
The National Weather Service has predicted a 70% chance that this will be the strongest El Niño in more than 70 years, according to NBC Bay Area. County leaders are preparing for above-average rainfall from December through March, and the station reports that the local emergency proclamation will help Sonoma County get an early start on staffing and training before storms hit. The move follows Cloverdale, which became the first city in the county to declare its own local emergency in September, citing flood risks to its water department supply wells, municipal airport, and a PG&E substation along the Russian River, as Healdsburg Tribune reported.
A Scientific Basis for the Early Warning
The county's declaration follows Governor Gavin Newsom's statewide State of Emergency two weeks earlier, issued to coordinate preparedness efforts statewide, per the same NBC Bay Area account. Newsom's proclamation, issued September 21, cited National Weather Service Climate Prediction Center diagnostics showing a greater than 90% chance of a very strong El Niño and a 75% chance of historic strength during fall and winter, according to CA.gov. The order directed state agencies to fast-track permitting and identify ways to cut red tape for flood preparedness, and Newsom has requested recommendations from the state's environmental protection and natural resources agencies, which must provide them by October 16.
A study published in the journal Science in August 2026 found that global climate change has increased the intensity of El Niño ocean-atmosphere events by more than 36%, according to the governor's office.
Why the Russian River Basin Is So Exposed
The lower Russian River has a long history of overwhelming its banks. Since systematic record-keeping began in 1940, the river has flooded the Guerneville area 38 times, according to Verisk.
More recently, a major atmospheric river event in February 2019 sent the river to 46.1 feet in Guerneville, leaving the town almost totally inundated and damaging or destroying 2,572 homes and businesses in the Guerneville area, Verisk reported. The flood left Guerneville completely isolated.
County officials are prioritizing community engagement with residents of mobile homes near the lower Russian River, per NBC Bay Area. County crews will continue preventive drainage clearing and road repairs in the meantime, the station reports.
What the Emergency Declaration Actually Does
For all the alarming river statistics, the declaration itself is largely an administrative tool. Under California Government Code Section 8630, a local emergency may be declared by the governing body or an official designated by local ordinance; when a designated official declares it, the governing body must ratify it within seven days and review it at least once every 60 days until conditions permit termination, according to FindLaw. The framework provides extraordinary powers, and a local emergency proclamation is a prerequisite for requesting some state or federal assistance.
Cloverdale's earlier emergency declaration, covered previously by Hoodline's report on the city's vote, shows that a Sonoma County city took formal action weeks before the countywide order. With Sonoma County's own declaration now in place, the county joins the state and Cloverdale in a coordinated push to prepare for a winter that forecasters say could bring above-average rainfall.
