It should have been an idyllic Labor Day weekend, the serenity of the High Sierra region of California providing a welcome respite from protests and a pandemic.
But about 200 people — many of them unaware that a rapidly growing wildfire was closing in on a popular campground area in the Sierra National Forest — found themselves suddenly trapped while trying to flee Saturday night into Sunday morning.
The very forest where they had come for a holiday escape now provided kindling that helped create a firestorm.
It took a treacherous rescue operation by military helicopters to evacuate them from the Mammoth Pool Reservoir area, the authorities said. Others posted videos on social media showing themselves escaping by driving through a labyrinth of fire and ash.
“We had to splash water on our hair because our hair was catching on fire,” Rylee Zukovsky said on Sunday. “I was shoveling so much water into my face that I was almost drowning myself.”
Ms. Zukovsky, 16, said she was rescued in a Chinook helicopter after taking refuge at the reservoir with her boyfriend, her mother and her mother’s boyfriend.
Her mother lives near the campground, which she helps run along with a nearby store. The store’s owner frantically tried to rescue her three dogs, said Ms. Zukovsky, who recalled diving into the reservoir when embers started to hit her.
There was little to no cellphone service, she said, explaining that it had taken 12 hours before she was rescued.
“Nobody knew helicopters were coming,” she said. “The Chinook just flew out of the smoke.”
Dozens of evacuees were packed into the helicopters. Two UH-60 Black Hawks and a CH-47 Chinook transported them to Fresno Yosemite International Airport, said Brad Alexander, a spokesman for the California Governor’s Office of Emergency Services.
About 20 people were injured, he said, and some were taken to hospitals. Two people remained in very serious condition from burns, Daniel Lynch, the director of emergency medical services for Fresno County, said on Sunday.
One of the burn patients, he said, was a 14-year-old girl being treated at the Valley Children’s Hospital in Madera, Calif. The others hurt were adults, who had injuries that included broken bones, lacerations and abrasions, he said.
The helicopters made three trips during the evacuation effort, with rescuers trying to shepherd as many people as they could because the conditions were getting worse, the authorities said.
Two people stayed behind, refusing to be evacuated, the Madera County Sheriff’s Office said on Twitter on Sunday. The sheriff said that 20 people were still waiting to be rescued as of late Sunday afternoon.
The Sierra National Forest covers more than 1.3 million acres at elevations ranging from 900 to 13,986 feet, according to the U.S. Forest Service. It is tucked between Yosemite National Park to the north and Kings Canyon National Park to the south. The rugged terrain and poor visibility challenged the rescue operation, the authorities said.
“We’re all in awe of the California National Guard pilots who were able to land and evacuate citizens during a firestorm like that,” Tyson Pogue, the sheriff of Madera County, said.
Sheriff Pogue said the fire was unlike anything he had ever seen.
“It’s almost hellish conditions,” he said. “We almost have fire and ash raining from the sky in some areas.”
The Mammoth Pool Reservoir, which is about 90 miles northeast of Fresno, is accessible by one two-lane road that was cut off during the fire, the authorities said.
Juliana Park was with four friends on a backpacking excursion near the Isberg Trail on Saturday when they noticed the fire and realized they had to turn back, two hours uphill, to their car.
A forest ranger helped guide them out of harm’s way, she said.
“Don’t stop — just drive through it,” Ms. Park recalled the ranger’s saying. “Just drive.”
Ms. Park said that the evacuation had been hampered by the lack of cellphone service, so the group used a paper map and directions from the forest ranger that were jotted into the notes app on an iPhone.
It felt like the fire was going to “come and grab the car,” she said.
The wildfire started on Friday near the communities of Big Creek and Huntington Lake and prompted several evacuations, the Forest Service said on Sunday. The cause was still under investigation.
Teddy Forscher, a camper, said he and a group of friends had abandoned two cars and their equipment on Saturday before moving on in one vehicle.
“It just didn’t seem worth it,” he said of returning to the campsite.
“It looks like it’s 8:30 at night,” Ms. Lightfoot said of the darkness from the fire.
“You can taste the smoke,” she said. “You can see red coming up the mountain. It just looks like the end of the world.”
Aimee Ortiz contributed reporting.