YOSEMITE NATIONAL PARK (CBS/AP/BCN) -- A wildfire outside Yosemite National Park nearly quadrupled in size Thursday, prompting officers to warn residents in a community nearby to evacuate their homes and leading scores of tourists to leave the area during peak season.
California Gov. Jerry Brown declared a state of emergency due to the huge Rim Fire, which threatened more than 2,500 structures and had led to the evacuation of thousands this week. It was one of several blazes burning in or near the nation's national parks and one of 50 major uncontained fires burning across the western U.S.
Brown said he declared the emergency because of the fire's continued growth that has "damaged natural resources, threatened homes and infrastructure" and Cal Fire crews were deployed to assist the U.S. Forest Service in battling the expanding blaze.
Fire crews from the all over the Bay Area were also dispatched to the fire scene. Members from the San Rafael Fire Department headed to Tuolumne County to join a strike team, while another strike team from Alameda County was headed to the area too; it included crews from Alameda County, Oakland, Fremont, the East Bay Regional Parks District and Hayward fire departments.
The cause of the wildfire was under investigation. More than 1,350 crews had responded to the area so far, according to the forest service.
Meantime, heavy smoke from the fire triggered an air quality alert in Reno and surrounding areas more than 150 miles away.
Washoe County Health District spokesman Phil Ulibarri said Thursday the air quality index had risen from the good range of 50 earlier in the day into the unhealthy range of 130 by afternoon. Between 100 and 150 is considered unhealthy for those with respiratory ailments, the elderly and young children.
Back near Yosemite, a new evacuation order was issued for Pine Mountain Lake, with evacuation centers set up in Sonora and other nearby areas.
As flames approached a section of Pine Mountain Lake with 268 homes in the afternoon, deputies went door-to-door to deliver the news and to urge people to leave, Tuolumne County Sheriff's Department Sgt. Scott Johnson said.
The evacuations were not mandatory, although Johnson stressed that the fire, smoke and the potential for power outages posed imminent threats.
"We aren't going to drag you out of our house, but when we are standing in front of you telling you it's an advisory, it's time to go," he said.
Fire officials said the blaze, which started Saturday, had grown to more than 99 square miles and was only 1 percent contained Thursday, down from 5 percent a day earlier. Two homes and seven outbuildings have been destroyed.
While the park remains open, the blaze has caused the closure of a 4-mile stretch of State Route 120, one of three entrances into Yosemite on the west side, devastating areas that live off of park-fueled tourism.
Officials also have advised voluntary evacuations of more than a thousand other homes, several organized camps and at least two campgrounds. More homes, businesses and hotels are threatened in nearby Groveland, a community of 600 about 5 miles from the fire and 25 miles from the entrance of Yosemite.
Camp Mather, a camp near Groveland run by the city of San Francisco's Recreation and Parks department, is being used to house 200 firefighters and their equipment.
The camp had been evacuated earlier this week and was not damaged in the blaze. The closure has also forced the cancellation of the Strawberry Music Festival, which was scheduled for Aug. 29-Sept. 2.
"Usually during summer, it's swamped with tourists, you can't find parking downtown," said Christina Wilkinson, who runs Groveland's social media pages and lives in Pine Mountain Lake. "Now, the streets are empty. All we see is firefighters, emergency personnel and fire trucks."
Though Wilkinson said she and her husband are staying put - for now - many area businesses have closed and people who had vacation rental homes are cancelling plans, local business owners said.
"This fire, it's killing our financial picture," said Corinna Loh, whose family owns the still-open Iron Door Saloon and Grill in Groveland. "This is our high season and it has gone to nothing, we're really hurting."
Loh said most of her employees have left town. And the family's Spinning Wheel Ranch, where they rent cabins to tourists, has also been evacuated because it's directly in the line of fire. Two outbuildings have burned at the ranch, Loh said, and she still has no word whether the house and cabins survived.
"We're all just standing on eggshells, waiting," Loh said.
The fire started about 7 miles from the San Jose Family Camp in the Groveland area, where 11 staff members and 99 students from Berkeley's Maybeck High School were evacuated, according to the city of San Jose, which runs the camp. There were no reports of damage to camp facilities, but the evacuation order remained in place.
Other camps near Groveland, including the city of Berkeley's Tuolumne Family Camp and the San Francisco-based Jewish summer camp Camp Tawonga, were also evacuated.
The governor's emergency declaration finding "conditions of extreme peril to the safety of persons and property" frees up funds and firefighting resources and helps Tuolumne County in seeking federal disaster relief.
Park officials said the fire has not impacted Yosemite park itself, which can still be accessed via state Routes 140 and 41 from the west, as well as State Route 120 from the east side.
Yosemite Valley is clear of smoke, all accommodations and attractions are open, and campgrounds are full, said park spokesman Scott Gediman. During summer weekdays, the park gets up to 15,000 visitors.
"The fire is totally outside the park," Gediman said. "The park's very busy, people are here. There's no reason that they should not come."
The Yosemite County Tourism Bureau based in Mariposa has been helping tourists displaced by the fire to find new accommodations in other park-area towns, said director Terry Selk.
The Hetch Hetchy Reservoir in Yosemite, which supplies water to San Francisco residents and businesses, is east of the fire area, and has also not been affected.
There are no impacts to water quality or the water delivery and supply system because of the fire.
"We are meeting all our delivery needs," San Francisco Public Utilities Commission spokesman Tyrone Jue said.
(Copyright 2013 by CBS San Francisco, the Associated Press and Bay City News Service. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)
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