The fast-moving blaze in the Bonny Doon area, about 10 miles northwest of Santa Cruz, grew to 700 acres after it broke around 3 p.m. Wednesday, and it was only 5 percent contained by the next morning. Mandatory evacuations were ordered for 500 residents in the heavily forested hills. Voluntary evacuations were in place for another 1,000 residents.
The fire threatened hundreds of homes and could spread to as many as 1,500 acres before being brought under control, Battalion Chief Paul Van Gerwen said.
A calm, cloudless sky over the flames proved to be a mixed blessing for firefighters Thursday. While the high winds from the day before had nearly died, temperatures were quickly rising, with 90-degree weather expected.
"It's getting hotter and drier. We'd like to see the humidity come up," Van Gerwen said.
Further south, the state's largest wildfire had charred more than 16,000 acres in the Los Padres National Forest and was only 16 percent contained.
The fire had spread east to a remote part of the Army's Fort Hunter Liggett base and was also moving towards the incident command post Thursday morning. No buildings or people were in immediate danger, and winds were driving the fire away from inhabited areas of the military base, said Manny Madrigal, a spokesman for the U.S. Forest Service.
"It's pretty remote where it's burning now," Madrigal said.
But, Madrigal said, evacuation plans for the military base were being developed.
The Santa Cruz fire flared just two weeks after another blaze two miles away scorched 4,200 acres and destroyed at least three dozen homes.
Jeanne Colbus, 60, who lives about five miles from Bonny Doon, said she and her 94-year-old mother quickly left their home after she saw smoke in the hills and received a call ordering them to evacuate.
"I was gardening and I looked up and saw that big column of smoke," Colbus said. "I'm scared. We don't have fire insurance for one thing. A lot of our things are irreplaceable."
In Butte County, several hundred homes were evacuated ahead of a fast-growing wildfire near Chico, about 90 miles north of Sacramento. The blaze, which started around noon Wednesday, had grown to 6,000 acres and threatened about 1,650 structures. It was only about 10 percent contained Thursday morning.
"We've had very active winds, low humidity and high heat. As you know, that's a recipe for disaster," said Joshpae White, a spokesman for the California Department of Forestry and Fire Protection. "It's very remarkable that no structures have been damaged. I think that's due to the very aggressive firefighting we've been able to do today."
Gov. Arnold Schwarzenegger declared a state of emergency in Butte County late Wednesday to free up additional firefighting resources. He declared another one in Santa Cruz County early Thursday.
"We are mobilizing and coordinating all of the resources necessary to fight these fires," Schwarzenegger said in a statement.
Hot temperatures, steady winds and tinder-dry vegetation created conditions exactly like those that fed the earlier blaze.
Those conditions also prevailed throughout the rest of Northern California, where hundreds of firefighters were deployed on fire lines from the North Coast wine country to the Central Valley.
For a second day, erratic wind gusts surprised firefighters who were overrun by flames.
Three firefighters were burned near Lincoln, about 25 miles northeast of Sacramento, when they were caught in a 65-acre grass fire burning in a dry rice field. Two of them had moderate to severe burns to their faces and arms, while the third was released from a hospital after treatment for minor facial burns.
All three were taken to the University of California, Davis Medical Center regional burn center, which was also was treating a firefighter who was injured Tuesday while trying to protect a mobile home near a grass fire southeast of Sacramento.
The injuries to four firefighters in less than 24 hours show just how fast and dangerous wind-whipped grass fires can be, fire experts said.
This week's hot, dry north wind, gusting to 40 mph, turns the grass to tinder and can send embers sailing far ahead of the main fire. Flames, even in grass just a foot tall, can reach 4 to 6 feet high.
The extreme fire danger is expected to last through Thursday, with temperatures hitting 100 degrees throughout the Central Valley. Felix Garcia, a meteorologist with the National Weather Service in Sacramento, said winds are expected to decrease, which would help the firefighting efforts.
Conditions already had improved from Tuesday, when wildfires damaged dozens of homes and thousands of acres across Northern California. Flames destroyed 32 homes in Stockton, 50 miles south of Sacramento, and 21 homes in Palermo, about 60 miles north of the state capital.
In Santa Cruz County, more than 50 people had arrived at the evacuation shelter at San Lorenzo Valley Middle School in Felton by Wednesday evening, said Red Cross spokeswoman Lindsay Segersin.
Bonny Doon residents Dana Price, 51, and her husband Skip, 57, had just come home when they got the mandatory-evacuation call and quickly packed up their computers, musical instruments and animals - two dogs, a parakeet and a cat.
"The sad thing is, as you're evacuating, you're walking around your house thinking, this might be the last time I see this picture, this might be the last time I'm doing this," she said. "It's really kind of sad. It's almost like saying goodbye."