Smoke from the La Tuna fire, which has burned more than 5,000 acres in the Verdugo Mountains area, is causing unhealthful air in some areas.
The South Coast Air Quality Management District on Saturday issued a smoke advisory for the eastern San Fernando Valley and Burbank, which is likely to see smoke and ash.
Officials also said the San Gabriel Valley and San Gabriel Mountains could see unhealthful air.
Hundreds of firefighters battled the blaze overnight and into the morning, and at one point, the flames were spreading in four directions amid intense heat and wild winds. Three homes have burned, but no injuries have been reported, officials said Saturday.
Firefighters faced another day of triple-digit temperatures in some inland areas of Southern California as a heat wave that has gripped the state continues. By Saturday afternoon, winds were blowing up to 17 mph in the area of the La Tuna fire, with humidity at 27%, which was almost 10 percentage points higher than the same time Friday.
Winds are forecast to calm down this evening in the area of the fire, according to Carol Smith, a meteorologist with the weather service. Temperatures should drop to the mid-80s overnight, and humidity is expected to increase as monsoonal moisture from Tropical Storm Lidia moves into the region, Smith said. The weather system could bring rain and thunderstorms, which raises the flash flooding risk for burned areas, she said.
More than 700 homes in the area are under evacuation, including 300 in Burbank, 250 in Glendale and 180 in Los Angeles, officials said.