By Steve Gorman

LOS ANGELES (Reuters) – California fire officials on Sunday reported significant headway battling the two largest of dozens of lightning-sparked blazes raging in and around the greater San Francisco Bay area since mid-August, though 60,000 people remained under evacuation.

As of Sunday firefighters had managed to carve containment lines around 56% of the perimeter of a colossal wildfire that has burned more than 375,000 acres across five counties north of the bay, including a swath of the Napa and Sonoma valley wine country region.

That marked a major gain from 41% containment listed a day earlier for the blaze, dubbed the LNU Lightning Complex fire, according to the California Department of Forestry and Fire Protection (CalFire).

Containment of a slightly larger fire called the SCU Lightning Complex, which has charred more than 377,000 acres in four counties east and south of the bay, grew to 50% on Sunday, up from 40% on Saturday, CalFire said.

Those two blazes together – which rank as the second- and third-largest wildfires on record in California – account for half of total acreage set ablaze during the past two weeks in a series of catastrophic lightning storms.

Firefighters, helped by cooler weather after a record-breaking heat wave abated, have gained ground elsewhere across the state, as well.

“We definitely have increased containment on all of the major fires, evacuations are being lifted and weather conditions are more favorable,” CalFire spokeswoman Christine McMorrow told Reuters by phone. “We are definitely making progress.”

Nearly 14,00 lightning strikes, mostly in central and northern California, have ignited hundreds of individual fires since Aug. 15, many of which merged into bigger conflagrations. Those fires have collectively charred more than 1.42 million acres – a landscape larger than the state of Delaware, according to CalFire.

Seven fatalities have been confirmed, and nearly 2,500 homes and other structures have been reduced to ruin. Smoke from the fires also badly degraded air quality throughout the region, adding to health hazards already posed by the coronavirus pandemic.

While CalFire said more than 60,000 residents remained displaced throughout the fire zone as of Sunday morning, McMorrow said “quite a few” evacuation orders and warnings were being lifted.

Meteorologists said the recent spate of dry lightning, the heaviest seen in California in more than a decade, was linked to the same atmospheric high-pressure system that caused a lengthy heat wave, which in turn further desiccated dense, fire-prone vegetation across the state.

Scientists point to lengthy droughts and longer-than-normal stretches of extreme heat as evidence of climate change that has steadily intensified and prolonged wildfire season in California and across the Western United States in recent years.

Climatologist Zach Zobel said California is on track to overtake the nearly 2 million acres burned in 2018, when the state suffered its deadliest wildfire in history, as well as the most acreage burned on record gong back to 1987.

(Reporting by Steve Gorman in Los Angeles; Editing by Robert Birsel)