Thousands of firefighters are battling to contain California’s Park Fire and other blazes across the West

Firefighters in Northern California race to contain the so-called Park Fire which reduced an area of ​​more than 1,400 square kilometers to ashes and darkened the sky with smoke and haze.

The sprawling fire – which officials say started after a man pushes burning car into ravine in Chico and then fled – was only 12% contained by Sunday. It has destroyed at least 66 buildings and threatened about 4,200 more homes.

Based on drone footage, authorities initially estimated that 134 structures had been lost, but after teams personally assessed the damage, they lowered that number.

“Unfortunately, that number is likely to increase,” Jay Tracy, a spokesman for Park Fire headquarters, told The Associated Press on Sunday. “Every day, that number could increase — our crews obviously don’t do damage inspections when there’s an active fire in an area.”

Lower temperatures and higher humidity could help firefighters tackle what is now the largest fire. the largest active wildfire in the country and the seventh largest in California history.

The fire is causing poor air quality across much of the northwestern US and western Canada.

The Park Fire has been compared to the 2018 Camp Fire that tore through the nearby community of Paradise, killing 85 people and burning 11,000 homes. Paradise and several other communities in Butte County were under evacuation warnings Sunday.

Cal Fire Operations Section Chief Jeremy Pierce had some good news for the area, however. He said around noon that the southernmost front of the Park Fire, closest to Paradise, was “looking really good,” with crews focused on clearing the area over the next three days. He also said they don’t expect the fire to move any further into Chico, a city of about 100,000 just west of Paradise.

Initially, responders focused on saving lives and property endangered by the Park Fire, but now they are focusing more on directly fighting the fire, Tracy said. About 3,400 firefighters are fighting the fireassisted by numerous helicopters and firefighting aircraft. Tracy said the reinforcements would provide much-needed respite for local firefighters, some of whom have been working nonstop since the fire began on Wednesday.

“This fire is surprising a lot of people with its explosive growth,” he said. “It’s kind of unprecedented.”

The Park Fire started on Wednesday. A Chico man accused of starting the fire was arrested Thursday and is scheduled to appear in court Monday.

The northern half of the fire remained a challenge Sunday, Pierce said, as firefighters used bulldozers and other equipment to build fire lines over rocky, difficult terrain and try to keep the flames from spreading.

The Park Fire was one of more than 100 blazes burning across the U.S. on Sunday, according to the National Interagency Fire Center. Some were caused by weather, as climate change increases the frequency of lightning strikes while the Western U.S. struggles with scorching heat and bone-dry conditions.

Despite improved fire weather in Northern California, conditions were still favorable for more fires to start. The National Weather Service warned of “red flag” conditions Sunday across much of Utah, Colorado and Wyoming, along with parts of California.

In Southern California, a fire in the Sequoia National Forest tore through the community of Havilah after burning more than 48 square miles (124 square kilometers) in less than three days. The town of about 250 residents was under evacuation orders.

Fires also raged in eastern Oregon and eastern Idaho, where officials were assessing damage from a cluster of fires known as the Gwen Fire, estimated at 40 square miles (106 square kilometers) in size Sunday.