Sonoma County supervisors declared a local emergency Tuesday as officials prepare for a winter that could bring heavy rain, flooding and mudslides if a strong El Niño develops. The county says forecasters put the chance of El Niño reaching historic levels this winter at 75%. The outlook signals a heightened risk, not a certainty of severe storms. The proclamation directs county departments, Sonoma Water and sanitation districts to prioritize infrastructure considered threatened or vulnerable. It also calls for coordination with cities, special districts, tribal partners and state emergency managers. County crews are clearing culverts and flood-control channels, inspecting roads and other locations with a history of flooding or landslides, and staging sandbags, barricades and equipment. Emergency managers are preparing for additional staffing and emergency operations, while systems for monitoring rainfall, streams and reservoirs are being readied for winter. “The best time to prepare for a flood is before a storm,” Board of Supervisors Chair Rebecca Hermosillo said in a county statement. The county action follows a statewide emergency proclamation issued by Gov. Gavin Newsom about two weeks earlier. The state said the anticipated impacts could require resources spanning multiple jurisdictions and mutual-aid regions.