SAN FRANCISCO (AP) — Thousands of firefighters across California were contending with dry conditions, strong winds and triple-digit temperatures as they battled raging wildfires that left some areas with smoke lingering in the air.

In Northern California, hundreds of evacuees were allowed to return home as crews continue to make progress against a wildfire that has now grown to about 5 square miles.

The blaze in Lake County is now 30 percent contained after nearly threatening 500 homes in the Spring Valley and Long Valley communities, state fire spokesman Daniel Berlant said Tuesday.

Those homeowners were allowed to return home Monday night as the fire is more active on the eastern edge which is unpopulated and plenty of open brush.

"Even though we've allowed the residents to return on the west side, this fire still has the potential to grow," Berlant said. "We're just fortunate that it has moved away from the homes while continuing to burn."

Berlant said while the more than 1,100 firefighters at the scene are putting out hot spots, they still faced with dry conditions and near 100 degree temperatures.

"It's been the heat, not the winds," Berlant said. "There's almost zero moisture inside the brush which hasn't burned in decades. It's very thick and overgrown."

A home and two structures have been destroyed in the fire, officials said.

Also in far Northern California, the Chips Fire in the Plumas National Forest continues to threaten about 900 homes and has prompted evacuation orders in the Seneca and Rush Creek communities.

On Monday, the Plumas County Sheriff issued a voluntary evacuation for residents in areas along Highway 70 as firefighters made progress with the fire along the northern edge. But, as crews expected, spot fires were beginning to emerge on Tuesday, along with slight winds and ash in the air, said Jennifer Velez, a fire spokeswoman.

The fire has burned about roughly 57 square miles and it remains 12 percent contained.

"We do have containment lines and, depending on what the forces of nature bring us, we're going to continue improving our lines and keep an eye on what lies ahead," Velez said. "We're responding as quickly as possible."

Also Monday, Plumas County health officials reissued a smoke advisory. The two blazes, as well as a fire in Solano County, affected air quality in the region as a thick haze enveloped the area on Monday and smoke could be smelled in the Sacramento Valley.

Winds likely carried the smoke into the valley, Christina Ragsdale, a spokeswoman for the Sacramento Metropolitan Air Quality Management District, said Tuesday.

"We definitely had some smoke problems overnight, but it has improved very significantly today," Ragsdale said.