Evacuation orders and advisories have been lifted for several Sierra Nevada communities once threatened by a raging wildfire in and around Yosemite National Park.
Officials say they are still investigating the cause of the blaze, which started 18 days ago in an isolated area of the Stanislaus National Forest and has burned nearly 960 square kilometres - the fourth biggest recorded wildfire in California.
With higher humidity and lower temperatures, the fire reached 80 per cent containment, prompting the sheriff's offices in Tuolumne and Mariposa counties to lift evacuation advisories for communities with several thousand structures in the fire's path.
Officials said 111 structures, including 11 homes, have been destroyed.
More than 4300 firefighters are still battling the blaze.
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Although no cause has been announced, one local fire chief speculated the fire might have ignited in an illegal marijuana crop.
Chief Todd McNeal of the Twain Harte Fire Department told a community group recently that there was no lightning in the area, so the fire must have been caused by humans.
"We don't know the exact cause," he said in a talk that was posted August 23 on YouTube.
"Highly suspect it might have been some sort of illicit grove, a marijuana-grow-type thing, but it doesn't really matter at this point."
The video was first reported on Saturday by the San Jose Mercury News.
Officials overseeing the fire suppression effort would not comment on the statement and would only say that the cause is still under investigation.
The US Forest Service is leading the investigation.
McNeal could not be reached for comment on Tuesday.
Illegal marijuana crops in national parks and forests have tormented federal land managers for years.
Growers hike into remote canyons with poisons and irrigation lines and set up camp for months.
The poisons kill wildlife and seep into streams and creeks. The growers leave tonnes of garbage behind.
The three top causes of wildfires in California are equipment use, such as a lawnmower blade hitting a rock or a vehicle's malfunctioning catalytic converter, plus debris burning and arson.
