County of Marin - News Releases - Red Flag Warning

For Immediate Release
September 19, 2021

Red Flag Warning in Effect for Marin County

Warning to remain in place until 8 p.m. Monday, September 20

Marin County, CA -- The National Weather Service issued a Red Flag Warning on Sunday, September 19, for large portions of California including the North Bay mountains in Marin County effective from 11 p.m. Sunday to 8 p.m. Monday for dry offshore winds for the North Bay and East Bay hills.

A Red Flag Warning means that critical fire weather conditions are expected during this time frame. Residents are advised to exercise extreme caution during the Red Flag Warning because a simple spark could cause a major wildfire, including the use of equipment and machinery as well as smoking.

Dry northerly offshore winds will push into the Napa hills around 11 p.m. Sunday and gradually spread over the North Bay and East Bay hills. The initial burst of winds will occur while humidity values remain fairly moist. However, the dry offshore winds will begin a rapid drying of the atmosphere with humidity values dropping quickly by Monday morning. Continued moderate offshore winds on Monday as humidity values drop into the teens. Offshore winds will ease by sunset Monday night. Little or no humidity recovery Monday night into Tuesday morning but with only light offshore winds.

For any land use restrictions or closures contact the appropriate land management agency:

  • The National Park Service Point Reyes National Seashore is 415-464-5100
  • The Mount Tamalpais State Park information number is 415-388-2070.
  • The Marin Municipal Water District information number is 415-945-1195.
  • The Marin County Fire Information Hotline number is 415-473-7191.

 Defensible space is essential to improve your home’s chance of surviving a wildfire.

To register for emergency alerts, visit To learn more about preparing for wildfire, visit


Jason Weber
Marin County Fire Department

33 Castle Rock Ave.
Woodacre, CA 94973
(415) 473-6717
Email: Jason Weber
Marin County Fire website