Gov. Gavin Newsom has declared a statewide emergency in order to help California respond to the fires burning across the state amid an extreme heatwave that brought more warnings about power outages on Tuesday.

More than 30 wildfires are burning across California, including nearly a dozen that started in the last two days, according to officials with the California Department of Forestry and Fire Protection and a Times analysis.

While the containment of some fires is increasing, other blazes are being sparked and are growing amid a combination of excessive heat and lightning from thunderstorms induced by a tropical storm in the Pacific Ocean.

Air quality was bad in many parts of the state due to the fires and weather. But the Bay Area and other parts of Northern California were hit particularly hard as winds carried smoke from multiple fires in places such as Marin, Sonoma, San Mateo and Monterey counties into communities. Experts say the air quality could be even worse on Wednesday.

The heat has continued to tax the state’s power supply. After rolling blackouts on Friday and Saturday, officials warned that more areas could lose power if people did not conserve. Blackouts were averted Tuesday when the California Independent System Operator called off power outages that had been anticipated statewide, crediting conservation efforts by consumers.

The Los Angeles Department of Water and Power did not institute rolling power outages either and provided excess power to Cal-ISO on Tuesday. Still, about 12,000 of its 1.5 million customers have been affected by outages — mostly for heat-related reasons such as overloaded equipment.

Newsom’s office said that the state had secured assistance this week from the Federal Emergency Management Agency to respond to fires in Napa, Nevada and Monterey counties.

“We are deploying every resource available to keep communities safe as California battles fires across the state during these extreme conditions,” Newsom said. “California and its federal and local partners are working in lockstep to meet the challenge and remain vigilant in the face of continued dangerous weather conditions.”

Crews on Tuesday battled fires that burned more than 50,000 acres across seven counties in Northern California and the Central Valley.

The SCU Lightning Complex, made up of about 20 fires, began early Sunday and involves areas of Contra Costa, Alameda, Santa Clara, Stanislaus and San Joaquin counties, according to California Department of Forestry and Fire Protection officials. It was 0% contained as of Tuesday afternoon.

Firefighters in Northern California also responded to the LNU Lightning Complex, where fires had burned more than 32,000 acres by Tuesday night. The incident includes five fires in Napa County and two fires in Sonoma County. All were 0% contained as of 8 p.m. At least 1,900 structures are threatened, and three have been destroyed.

Evacuation orders have also been issued in the mountains along the borders of San Mateo and Santa Cruz counties.

Cal Fire Capt. Richard Cordova said most of the biggest fires — including several in the Central Valley and Northern California — are believed to have been caused by lightning strikes, which can ignite dry grasses and brush.

The River fire in Monterey County, which has burned through more than 4,000 acres and is 10% contained, as well as fires in San Mateo and Santa Cruz counties — including the CZU August Lightning Complex, which has burned through 1,000 acres and has no containment — pose threats to the population, Cordova said.

The River fire has already destroyed six structures and damaged two others, according to Cal Fire. More than 1,500 structures remain threatened by the blaze, which has prompted mandatory evacuations.

“We had this kind of occurrence happen in 2008, where we had numerous lightning strikes and fires in that region,” Cordova said. “It’s a little late in the thunderstorm season, but not a rarity to see these lightning events take place.”

Firefighters are battling flames amid an intense heat wave that began late last week and has set record-high temperatures across California. On Sunday, the mercury in Death Valley reached 130 degrees — possibly the highest mercury reading on Earth in almost 90 years.

“The heat wave is certainly not helping things,” National Weather Service meteorologist Mike Wofford said of the fires, adding that the heat is not only an increased fire risk, but also a burden on firefighters. “It’s been a tough few days, and it’s going to stay pretty hot during the week.”

Storms have also made matters worse. Humidity from the Southeast is a source of some of the state’s thunderstorms, Wofford said, and although rain can help dampen fires and assist in containment efforts, gusty winds created by the storms can be hazardous.

In Southern California, Wofford said that thunderstorms have been contained mostly to the mountains, where the Lake fire in the Angeles National Forest has raged for more than a week. The blaze has burned through more than 22,000 acres and was 38% contained as of Tuesday evening.

In neighboring Ventura County, the Holser fire erupted Monday afternoon near Lake Piru and has burned at least 3,000 acres.

Among the largest fires in the state — the Apple fire in Riverside County, which began July 31 — is now 95% contained after burning more than 33,000 acres. The blaze was ignited by a malfunctioning car, Cal Fire officials said.

The fire prompted evacuation orders across the Inland Empire, which were complicated by the coronavirus pandemic. Designated evacuation centers were abandoned in favor of hotels in order to stem the potential spread of the illness among people in close quarters.