GILROY, Calif. (AP) — Firefighters took advantage of cooler temperatures and calmer winds Saturday as they continued to fight a persistent wildfire in the Santa Cruz Mountains that has chewed through acres of centuries-old redwoods, destroyed at least 17 homes and displaced hundreds of people.

Efforts were also helped by the higher humidity, but a possible storm could bring lightning and stronger winds that could spread the fire, officials said.

The fire was about 25 percent contained and expected to grow to more than 6 square miles before it's brought under control, fire officials said. It has burned more than 5 square miles and destroyed 28 structures. Another 500 buildings were threatened.

Almost 2,000 residents remained under evacuation orders — more than 450 of them mandatory — while more than 3,000 personnel and a swarm of air tankers, helicopters and fire engines were deployed to the area, said Dave Shew, a battalion chief with the California Department of Forestry and Fire Protection. One firefighter suffered minor heat-related injuries.

"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."

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

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

Shew said the cost of battling the blaze has risen to about $1.7 million and he expects the containment effort to continue through the weekend. Crews were focused on building fire lines to keep the blaze from growing, he said.

Officials were investigating the cause of the fire, which was first reported Thursday morning in the mountain range that separates Santa Cruz and Santa Clara counties. The area, about 15 miles south of San Jose, is rural but dotted with homes.

"I feel a great sadness in my heart for everybody who is involved in this event," said Kenneth Rich whose house was destroyed. "It's devastating."

To the south, the stormy weather in Southern California that got the Memorial Day weekend off to a soggy start was expected to continue through Saturday before clearing, said Stuart Seto, a weather specialist with the National Weather Service in Oxnard.