The Bay Area Air Quality Management District has issued an air quality advisory for Thursday and Friday because of a large wildfire in Butte County that is expected to send smoke into the region.
The advisory was issued Thursday morning following the start of the Camp Fire northeast of the Bay Area, according to the air district.
The Sonoma County Sheriff's Office put out a message Thursday morning saying smoke is already visible in the county.
"There are no major fires reported in Sonoma County at this time but let's all be very careful," sheriff's officials said in the message.
PG&E has been mulling whether to proactively turn off power in certain counties at risk of wildfires. A red flag warning has been issued by the National Weather Service through Friday because of high winds and low relative humidity.