The Associated Press

LOS ANGELES (AP) - A growing wildfire in the mountains north of Los Angeles spread over nearly 9 square miles of bone-dry forest Saturday, forcing evacuations and sending up massive billows of smoke that were hampering air operations, officials said.

"It's difficult for water-dropping aircraft to get in there, but they're still trying," said Forest Service spokesperson Jessica Luna.

The blaze in the steep San Gabriel Mountains above La Canada Flintridge continued to moveout in all directions, the most active flanks to the north, deeper into the forest, and east, Luna said.

The fire was 5 percent contained.

The flames burned increasingly lower down the edges of the mountains and crept toward the northeast edge of the city of Altadena, where some residents were ordered to evacuate.

Hot, dry weather was expected all day Saturday, but crews were hopeful that winds would remain light, Luna said.

A major goal was to keep the fire from spreading up Mount Wilson, where many of the region's broadcast and communications antennas and the historic Mount Wilson Observatory are located, officials said.

Authorities issued a mandatory evacuation notice early Saturday for 150 homes located within a half-square-mile area and on the slopes of the San Gabriel Mountains. An evacuation center was set up at La Canada High School.

Hundreds more residents were packed and ready to move on a moment's notice.

"We're boxed up and ready to go," said La Canada Flintridge resident Steve Buntich, watching helicopters line up to siphon water from a golf course reservoir. He said his wife and children had evacuated to a friend's house for several hours, but had since returned home.

A thick layer of smoke hovered over northern Los Angeles County, and officials issued a smoke advisory for communities near the fire. Residents were urged to avoid exertion and seek air-conditioned shelter.

A second fire in the Angeles National Forest was burning several miles to the east in a canyon above the city of Azusa. The 3.4-square-mile blaze, which started Tuesday afternoon, was 85 percent contained Saturday. No homes were threatened, and full containment was expected by Monday.

A wildfire on the Palos Verdes Peninsula on the south Los Angeles County coast was 90 percent contained Saturday morning, according to County Fire Captain Mike Brown. As many as 1,500 people were forced to flee at the height of the fire Thursday night. Six homes received minor exterior damage, but the only structures destroyed were an outbuilding and gazebo. No injuries were reported.

Southeast of Los Angeles in Riverside County, a 3O-square-mile fire in a rural area of the San Bernardino National Forest was 10 percent contained. Crews aided by aircraft were working to build a line around the fire, which was burning in steep, rocky terrain in Beeb Canyon, according to Forest Service spokesperson Norma Bailey. No structures were threatened. Temperatures were expected to top 100 degrees in the region, but winds remained light.

To the north, in the state's coastal midsection, a 9.4-square-mile fire threatening Pinnacles National Monument kept 100 homes under evacuation orders near the Monterey County town of Soledad. The blaze, 60 percent contained, was started by agricultural fireworks used to scare animals away from crops. The fire destroyed one home.

In the southern part of Monterey County, firefighters had 100 percent containment of a 5-square-mile fire that had threatened 20 ranch homes.

Gov. Arnold Schwarzenegger declared a state of emergency Friday in Los Angeles and Monterey counties.

"It's fire season, clearly," he said. "There's tremendous amount of heat all over the state."

A state of emergency was declared Saturday for Mariposa County, where a nearly 4.1-square-mile fire burned in Yosemite National Park. The blaze was 15 percent contained, said park spokesman Scott Gediman. No structures were threatened.

Park officials closed a campground and a portion of Highway 120, anticipating that the fire would spread north toward Tioga Road, the highest elevation route through the Sierra. The number of firefighters was expected to double over the weekend to 1,000.

TheMariposa County Sheriff's Office ordered guests and staff at the Yosemite View Lodge, just outside the park's western gate, to evacuate Friday due to the fire. People without lodging were offered beds in a shelter in Mariposa staffed by the Red Cross.

Associated Press Writers Sudhin Thanawala in San Francisco, Garance Burke and Tracie Cone in Fresno and Christina Hoag and Solvej Schou in Los Angeles contributed to this report.