The National Weather Service says a funnel cloud touched down near Roseville shortly after 6:15 p.m. Wednesday.
Fire Department Division Chief Kathy Finney tells the Merced Sun-Star that 12 houses suffered roof damage and six reported fence damage. No injuries are reported.
The weather service says a tornado also touched down in Ordbend, in Glenn County. KNTV says there are reports of at least four twisters, which are rare for California.
The northern half of the state is experiencing wild weather including thunderstorms packing heavy winds.
Showers are likely to continue through the weekend.