(CNN) -- A fast-growing wildfire threatened scores of homes in Napa County, California, officials said Tuesday.
About 150 residences some 22 miles from the town of Napa were evacuated, Cal Fire spokesman Daniel Berlant said.
"We're experiencing conditions we normally see in late summer or fall," he said.
Dry conditions are fueling the blaze, he said, adding that it isn't very windy.
Still, the fire grew to 2,500 in a matter of hours Tuesday. About 30% of the fire has been contained.
"It's very scary. We're keeping an eye out," said Sally Kimsey, the owner-operator of a combination winery and veterinarian clinic.
The fire was about a mile from her property. She said she had evacuated some horses and was lining up trailers in case the fire got closer.
CNN's Dave Alsup contributed to this report.