The counties of Sonoma and Napa will be conducting a targeted emergency alert and warning test this Thursday, according to officials.

The exercise will take place along with local law enforcement and fire agencies and will be a test of the Wireless Emergency Alert, or WEA, for the evacuation zone of SON-6F4, which is in the Sonoma Valley near the Sonoma-Napa county line. The zone only has about 400 residents.

The alerts will go out from 10:45 a.m. to 11:30 a.m. on Thursday. It is not an evacuation exercise, just a test of the alert warning system, Sonoma County said.

A map highlights Sonoma County evacuation zone SON-6F4, where a Wireless Emergency Alert test will take place Thursday, March 27, 2025. (Sonoma County Emergency Management)

The WEA alert system broadcasts to a targeted geographical area, much like federal systems which alert people to emergencies via text. Residents should have their phones on and make sure the phone’s sounds are on as well, the county said. WEA is a national service and there is no need to sign up to be notified.

More information about the WEA tests can be found online. A complete map of all the Sonoma County evacuation zones can be found on the county’s website.

Katy St. Clair got her start in journalism by working in the classifieds department at the East Bay Express during the height of alt weeklies, then sweet talked her way into becoming staff writer, submissions editor, and music editor. She has been a columnist in the East Bay Express, SF Weekly, and the San Francisco Examiner. Starting in 2015, she begrudgingly scaled the inverted pyramid at dailies such as the Vallejo Times-Herald, The Vacaville Reporter, and the Daily Republic. She has her own independent news site and blog that covers the delightfully dysfunctional town of Vallejo, California, where she also collaborates with the investigative team at Open Vallejo. A passionate advocate for people with developmental disabilities, she serves on both the Board of the Arc of Solano and the Arc of California. She lives in Vallejo.