Fresno, California – Extremely hazardous travel conditions are expected across California’s San Joaquin Valley as dense fog reduces visibility to dangerously low levels, prompting a Dense Fog Advisory that impacts major transportation corridors including State Route 99, Interstate 5, and Highway 198.
According to the National Weather Service in Hanford, a Dense Fog Advisory remains in effect until noon Sunday, with visibility likely dropping below 200 feet and potentially to near zero in some locations. The advisory covers much of the San Joaquin Valley, where fog has developed overnight and is expected to persist through the morning hours.
Forecasters describe the situation as a Very High Transportation Risk, particularly during the overnight and early morning commute. Dense fog can cause sudden whiteout conditions, making it difficult for drivers to see other vehicles, lane markings, or traffic signals until it is too late to react.
Roadways most affected include CA-99 through Fresno, Visalia, and Bakersfield, I-5 across western valley routes, and connecting highways such as CA-41, CA-43, and CA-180. The National Weather Service warns that traffic slowdowns, delays, and chain-reaction crashes are possible due to rapidly changing visibility.
Motorists are urged to slow down, use low-beam headlights, and increase following distance. High-beam headlights are discouraged, as they can worsen glare in dense fog. Drivers should also be prepared for sudden stops and avoid unnecessary travel during peak fog conditions if possible.
In addition to reduced visibility, the fog may contribute to damp road surfaces, further complicating driving conditions during the morning hours.
The National Weather Service notes high confidence that dense fog will redevelop each night and morning into the coming week, meaning repeated travel impacts are likely until weather patterns change.
Residents and travelers are encouraged to monitor local forecasts closely and allow extra time for travel. Even short trips can become hazardous when visibility drops to near zero with little warning.
