Santa Rosa, Calif. – Drivers across the North Bay interior valleys face dangerously low visibility early Thursday as dense fog reduces sight distance to a quarter mile or less along US-101, CA-12 and surrounding roadways until 11 a.m.
Morning commuters have little margin for error. Visibility can drop rapidly within a few hundred feet, especially in low-lying areas near Santa Rosa, Petaluma and Sonoma. Portions of CA-29 through Napa Valley and CA-37 approaching Novato are also vulnerable to sudden whiteout conditions in fog-prone stretches.
According to the National Weather Service in San Francisco, a Dense Fog Advisory remains in effect through 11 a.m. Thursday for the North Bay interior valleys. Forecasters warn that additional advisories could be issued for other parts of the Bay Area and Central Coast if visibility continues to deteriorate overnight and into the morning hours.
Low visibility increases the risk of chain-reaction crashes during peak commute times. Bridges, overpasses and rural two-lane highways without median barriers pose the greatest concern as drivers may not see stopped traffic ahead until it is too late.
Motorists should use low-beam headlights, not high beams, and leave several car lengths between vehicles. Reduce speeds below posted limits and allow extra time to reach destinations safely.
Conditions are expected to gradually improve late Thursday morning as daytime heating helps lift the fog. Officials may extend advisories if dense fog lingers longer than anticipated across the North Bay.
