Carolyn Dusharme, 81, was pronounced dead at the scene of the 9:50 a.m. crash near the intersection of Fifth Street West and Leveroni Road outside of Sonoma, CHP Officer Jaret Paulson said.
Dusharme drove south on Fifth Street West through a four-way stop and continued driving half a mile through the T-intersection at Leveroni Road, Paulson said.
The car went through a metal guardrail and into a field, missing two trees, Paulson said.
The Mitsubishi then dove nose first into a creek and flipped onto the driver's side, Paulson said.
Alcohol or drugs are not considered factors in the crash, Paulson said.