Gov. Jerry Brown has declared a state of emergency in Napa and Lake counties due to the Valley Fire, which grew to 40,000 acres in less than 24 hours after starting Saturday afternoon.
According to a proclamation issued by Brown Sunday morning, the California National Guard has been mobilized to help fight the fire, which started in Lake County and spread into Napa County.
The fire has now burned an estimated 40,000 acres and is zero percent contained as of this morning, according to Cal Fire officials.
Four firefighters who were part of a helicopter crew were injured Saturday. The firefighters suffered second-degree burns, but are in stable condition at the UC Davis Medical Center, according to Cal Fire spokesman Daniel Berlant.
Mandatory evacuations have been ordered in Lake County from state Highway 29 and state Highway 175 to Seigler Canyon Road and for state Highway 29 at state Highway 175 toward Cobb and Red Hills Road to state Highway 29.
More than 1,000 firefighters are fighting the fire and getting people evacuated from the area.
Areas of Napa County are under advisory and could be under mandatory evacuations later today.
Cal Fire is reporting there have been an unconfirmed number of structures destroyed in the fire.