LOS ANGELES — Firefighters made progress Monday against wildfires from Santa Barbara to San Diego as parched Southern California headed into a summer heat wave.

More than 600 firefighters gained on a 482-acre fire in Los Padres National Forest northwest of Santa Barbara. The fire, which started Saturday evening, was 80 percent contained, said U.S. Forest Service spokesman Joe Pasinato.

Full containment was expected today. The cause remained under investigation.

About 30 firefighters and other personnel from the Ventura County Fire Department joined the fight against the Rancho fire over the weekend, said Spokesman Tom Kruschke. Kruschke said he expected the department's employees to head home Monday.

The Ventura Fire Department sent two firefighters and a water tender to the Rancho fire, said Assistant Chief Kevin Rennie. They will likely stay in the area for several more days.

Near the town of Julian, about 60 miles northeast of San Diego, the 170-acre Banner fire and 60-acre Deer fire were c ontained.

The fires' origins were considered suspicious, said Roxanne Provaznik of the California Department of Forestry.

On Sunday, Los Angeles County firefighters contained a 50-acre blaze that spread from a recreational vehicle fire along Interstate 5 near Pyramid Lake, officials said.

To the north in Kern County, the 12,400-acre White fire was expected to be fully contained today. Thirteen residences and 18 outbuildings were destroyed during the fire, which broke out June 24.

During the weekend, Los Angeles ended its driest rain-year on record with just 3.21 inches of precipitation downtown between July 1, 2006, and June 30, 2007. That's nearly 12 inches less than normal.

Forest Service officials reminded visitors, ahead of the July 4 holiday, that all fireworks are prohibited on national forest land and restrictions on campfires were in effect.

With triple-digit temperatures forecast through much of the week in Southern California valleys and high desert, the Los Angeles County health officer issued a public health alert. People were warned to take precautions against dehydration, heat cramps, heat exhaustion and heat stroke.

In Northern California, the wildfire that destroyed at least 254 homes south of Lake Tahoe was 100 percent contained Monday morning, fire officials said.

Hundreds of firefighters were heading home Monday, with no more than 200 expected to remain by evening — down from more than 2,000 at the fire's peak, said Scott Swanson, a fire information officer.

Environmental teams were moving into the fire-damaged forest to figure out how to minimize erosion into the crystal-blue waters of the lake, Swanson said.

Nearly all mandatory evacuation orders and road closures have been lifted, but all national forest land within the 3,100-acre fire perimeter was being closed to the public because of danger posed by falling trees, officials said.