LOS ANGELES — For more than a week, the typically blue sky above the Angeles National Forest was hidden behind a thick veil of gray smoke. Mountains usually visible for miles could barely be seen up close.
Fueled bytriple-digit heatand dry brush untouched by flames for more than 60 years, the Bobcat Fire continues to elude firefighters two weeks after it erupted in the San Gabriel Mountains. Fire officials point to steep terrain and changing winds as two of many factors making the wildfire east of Los Angeles especially challenging.
L.A. County Fire Chief Daryl Osby recently emphasized a third challenge: Firefighting resources across the state are strained by the worst fire season in California history.
“Five of the top 20 fires to ever burn in the state of California are burning right now in Northern California, which has challenged us in getting some of the resources here that we would normally get,” Osby said Friday. “The fire behavior that we’re getting in this fire and throughout the state of California is unprecedented.”
The cause of the Bobcat Fire, which has charred more than 91,000 acres and was 15 percent contained Saturday, has not been determined, the U.S. Forest Service said. About 1,600 personnel areassigned to fight it,a number that would normally be above 2,000 for a fire this size, said a spokesman for the Angeles National Forest.
Many area residents remain watchful as fire officials issue evacuation orders, lift them and issue new ones for neighboring areas. Checking air quality before venturing outside for a walk or jog has become a daily occurrence. People are advised to keep an emergency kit near their front doors or inside theirs car should they suddenly have to flee.
On Saturday, people living in nearby desert cities were ordered to evacuate. Last week, residents on the southern boundary of the fire in the San Gabriel Valley were told to leave their homes.
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“It’s been a stressful week,”Monrovia resident Anna Howie told NBC News. “I don’t think I’ve gotten three or four hours of sleep each night.”
Monrovia resident Michael Kunch said he has experienced many California fire seasons but “this has been the scariest.”
The fire was stuck at 0 percent containment for several days but then steadily grew to 3 percent as firefighters rushed to protect the historic Mount Wilson Observatory. Founded in 1904, the observatory once hosted groundbreaking astronomers like Edwin Hubble and is home to dozens of irreplaceable telescopes.
Containment grew to 6 percent last week, only to fall back to 3 percent later as winds shifted and strengthened. At one point, the fire came within 500 feet of the observatory, forcing employees to evacuate and firefighters to make an aggressive stand in a national forest where elevation ranges from1,600 feet to more than 10,000 feet.
By Thursday, containment was up to 9 percent and nearly doubled to 15 percent on Friday.
But as containment grew, so did the fire. It was approximately 70,000 acres Friday morning but 24 hours later had spread to more than 91,000 acres.
Officials estimate that damage to structures has been minimal, but affected homeowners say they are devastated by the destruction.
“I have been heartbroken over the loss,” Deb Burgess, president of the Sturtevant Camp board, said in an email.
Burgess owns a cabin at the historicSturtevant Camp, a cluster of cabins dating to 1893 that can be reached only by foot or horseback. She has not been allowed to visit the site and fears the Bobcat Fire may have destroyed it.
Locals worry that 80 cabins in the neighboring Big Santa Anita Canyon were also destroyed or damaged.
“These are really rare circumstances,” said Andrew Mitchell, spokesman for the Angeles National Forest. “It’s the most horrible thing in the world when you see a home burn. We’re really trying to focus on that.”
Firefighters are deploying every weapon in their arsenal as the Bobcat Fire continues to rage. They are bulldozing control lines along its perimeter to try to slow it down. Planes and helicopters are dumping water and fire retardant when possible, although smoky conditions made flying impossible for several days last week.
On the ground, firefighters are cleaning up “slop,” spot fires that jump control lines, and using small, controlled fires to preempt a bigger, more ferocious flank from igniting.
“This is a perfect storm,” Mitchell said. “Every fire has its individual challenges and you have to adapt to those challenges.”
Alicia Victoria Lozano is a Los Angeles-based digital reporter for NBC News.