(CNN) -- It was a rare bright spot on an otherwise hazy, smoke-filled horizon.
An evacuation advisory was lifted Thursday for residents in Tuolumne City, a picturesque community in northern California threatened by an historic wildfire, as firefighters worked to get a grip on the blaze.
Known as the Rim Fire, the conflagration has charred nearly 200,000 acres, cost the state more than $39 million to date and is threatening 5,500 structures, of which 4,500 are residences. It's the sixth-largest wildfire in California history. On Thursday, it was in its 12th day and it had only been contained 32%, according to Cal Fire.
Because of the approaching flames, officials have shut down electricity generators, and San Francisco -- more than 120 miles to the west -- temporarily is getting power from elsewhere.
While the Yosemite Conservancy says the Rim Fire has consumed tens of thousands of acres inside Yosemite National Park, it has so far had little or no direct impact on Yosemite Valley, a popular spot for tourists and home to many of the park's iconic attractions, including the El Capitan rock formation.
Firefighters hope to keep it that way. Nearly 5,000 people have been assigned to the blaze.
"This is going to be a tough fire," said Tom Tidwell, chief of the U.S. Forest Service. "It's going to continue for a few more weeks."
'It looked like a thunderhead cloud, but it was smoke'
The blaze has created challenges not only to firefighters and utility providers, but also to people who were in the park on long-planned explorations and expeditions.
That group included people such as David Hermanson and his friends.
They were on a 10-day trek through the wilderness, just four guys and six llamas. Expecting to commune with nature, they instead faced its sheer, raw power when their hike was cut short by the huge wildfire ravaging northern California.
Hermanson, a 30-year-old artist and air conditioner repairman from the San Diego area, knows Yosemite National Park like the back of his hand.
"Me and my dad have been hiking Yosemite every year since I was seven," he said.
Stoked to be back in the park again, Hermanson and three of his buddies loaded up the llamas and embarked August 20 on what was to have been a 60-mile hike from Leavitt Meadows to Lake Eleanor.
The group was at Dorothy Lake -- about halfway into their trip -- when clouds started to roll in. At least that's what they seemed to be.
"It looked like a thunderhead cloud, but it was smoke," Hermanson said. "It was just amazing. It looked surreal."
Time to turn around
Hermanson used a satellite phone to call his dad, who kept the group apprised as the wildfire gobbled up acres by the thousands.
"It was pretty bad in the evening," Hermanson said. "You couldn't see the other side of the lake, the visibility was maybe 100 yards."
Dad said it was time to turn around. The fire was spreading to the end of the trail.
"We didn't feel endangered," a disappointed Hermanson said. "We were just engulfed with smoke. It seemed like the smoke got worse as it progressed."
'A lot of work to be done'
Authorities say the Rim Fire started on August 17. The cause is under investigation.
"There's a lot of concern, and there's a lot of work to be done," U.S. Forest Service spokesman Lee Bentley said.
Firefighters have been able to build fire lines in several locations, officials say. The forecast is looking favorable as daytime highs sink into the 70s over the Labor Day weekend, a break from the temperatures in the high 80s firefighters were facing Wednesday.
More than 20 helicopters and air tankers were aiding the efforts.
Herman says the group's decision to abort their hike was a good one.
The rendezvous truck they had left at the end of the trail was nothing by a burnt shell after the fire roared through Lake Eleanor.
The group made it out safely on Monday. Hermanson's dad provided the ride home for the crew.
And the llamas?
"They were sneezing a lot. I think they may have been bothered by the smoke."
CNN's Dana Ford, Gary Tuchman and David Simpson contributed to this report.