The Associated Press

GILROY, Calif. — Firefighters took advantage of cooler temperatures and calmer winds Saturday as they struggled to gain control of a wildfire that has burned centuries-old redwood forests, displaced hundreds of residents and destroyed at least 17 homes in the Santa Cruz Mountains.

Strong overnight winds up to 45 miles per hour caused the blaze to grow to more than 3,400 acres and spread from Santa Cruz County to Santa Clara County early Saturday, according to the California Department of Forestry and Fire Prevention. About 50 homes in the small community of Sveadal near Uvas Canyon County Park were evacuated.

Firefighting efforts were helped by lower temperatures, lighter winds and higher humidity Saturday, but officials were concerned that a possible storm could bring lightning and heavier drafts that could cause the fire to spread, Battalion Chief Dave Shew said.

The fire was still only about 25 percent contained Saturday and was expected to grow to 4,000 acres before it's brought under control over the next week, fire officials said. One firefighter suffered minor heat-related injuries.

The fire that started Thursday has destroyed 28 structures and threatens another 550 buildings in the mountainous region about 15 miles south of San Jose.

"As long as we don't have this fire contained, then the homes are still threatened," Shew said. "We don't consider this to be anywhere near contained. I wouldn't say we're out of the woods yet."

More than 3,000 personnel, seven air tankers, 12 helicopters and 144 fire engines were being deployed to battle the blaze. Crews were focused on building fire lines to keep the blaze from getting bigger, Shew said.

Smoke from the wildfire has left a haze over the San Francisco Bay area that was expected to linger through the three-day Memorial Day weekend.

Gov. Arnold Schwarzenegger visited the Santa Cruz Mountains to assess the damage Friday and declared a state of emergency in Santa Cruz County to allow access to funds for the effort.

About 2,000 residents have been asked or ordered to evacuate their homes since the fire started, and officials say it's still not safe for them to return, Shew said.

The cause of the fire is still under investigation.