NAPA COUNTY, Calif. (KGO) -- Crews are working nonstop to get a handle on a wildfire burning in Napa County. Buildings are burned, homes have been evacuated, and the fire is just too unpredictable for anyone to go home.
On Wednesday, cooler temperatures and higher humidity helped the 1,000 firefighters on the front lines. The fire has been burning since around noon on Tuesday and it continues to grow.
The wildfire has burned 3,800 acres and has damaged two residences and seven outbuildings. Officials say 380 structures are threatened. The wildfire is 30 percent contained and no injuries have been reported. The cause is still unknown.
The flames are just north of the wineries in Napa Valley, off Butts Canyon Road in Pope Valley. Evacuations are still in effect for people living in the Berryessa Estates area.
For firefighters, overnight inversion layers present opportunities -- the wind dies down and temperatures drop. If crews are lucky, those conditions persist after sunrise. And that's what happened in Pope Valley Wednesday morning, though no one took the brief inversion layer for granted.
That's because hotspots can be capricious; a gust here, a puff there, and a blast of flames at the most unpredictable of places.
That's what happened in Pope Valley when the inversion layer lifted Wednesday afternoon.
As firefighters worried about containing the large perimeter, they also battled countless flareups inside the lines. One along Butts Canyon Road Wednesday afternoon came out of nowhere and took a small army to knock down.
As dramatic as it looked, it was nothing compared to Tuesday. And that's the good news.
The fast-moving blaze began Tuesday afternoon and within hours covered 600 acres and then spiked to 2,700 acres by late evening as it spread northeast into neighboring Lake County. State firefighters and crews from Napa, Lake and Solano counties spent the day working in 90-degree weather.
"This fire exploded because the conditions are so dry all across California," said state fire spokesman Daniel Berlant. "We were definitely surprised by this one."
State fire spokeswoman State McCambridge said Wednesday that the fire is not affecting the lucrative Napa Valley vineyards. Pope Valley is about 20 miles north of Napa Valley.
Cate Conniff, a spokeswoman for the Napa Valley Vintners, a nonprofit trade association, agreed. "It has not come anywhere close to what we consider Napa Valley wineries. It is moving in the opposite direction, and it continues to move that way. We're keeping an eye out on it," Conniff said
Gov. Jerry Brown said Wednesday that he has secured federal funds to help fire departments absorb some of the cost of fighting the fire.
Elsewhere in California, firefighters were surrounding a blaze in Shasta-Trinity National Forest that forced the evacuation of about 15 homes. Forest spokeswoman Andrea Capps said the fire has burned through 35 acres since it started Tuesday and was 70 percent contained.
(ABC7 News reporter Wayne Freedman and The Associated Press contributed to this report)