Firefighters prepare for a long-haul battle as the Dolan Fire in Big Sur expands in all directions.

With fires burning all over California, the sky was already filled with smoke even before the Dolan Fire started in Big Sur around 8pm on Tuesday, Aug. 18. 

And it's the smoke from those other fires that Incident Cmdr. Chip Laugharn blames for inhibiting firefighters' ability to battle the blaze from the air, due to low-visibility conditions, and, in turn, the fire getting an opportunity to grow unabated. 

"If we had clean air yesterday, we would've had a chance to lock it off. We lost that window," Laugharn says on Thursday. 

Without that opportunity, he says, "It's going to be a long-duration event." 

As of 5pm Thursday, the fire is estimated to be about 8,000 acres, up from 6,800 acres on Thursday morning. It's difficult for officials to get a good estimate on size because of limited air access—besides inhibiting their ability to fight the fire, smoky skies mean they can't get a complete view, either. The fire remains zero-percent contained. 

This fire has been unusual in that it has been spreading primarily overnight, when the wind has been picking up. While it's moving mostly to the south, Laugharn says it's spreading in all directions. "The first night of the fire was bad, out of control," he says. 

As the U.S. Forest Service, the lead agency fighting this fire, prepares for a long-haul firefight, officials are looking for a location to set up a fire camp. Roughly 250 people are currently fighting the fire, with crews from Idaho and Nevada on their way. 

Caltrans has been assisting by clearing fallen burnt logs, rocks and other fire debris from Highway 1 to keep it clear for fire engines.

The one successful containment effort firefighters have made is keeping the fire from jumping to the west side of Highway 1; while the west side has very few structures to protect, Laugharn says the terrain is so steep that it's virtually impossible to fight a fire there, and it could burn uncontrolled up and down the coast. 

Sara Rubin contributed to this report.