SAN ANDREAS, Calif. -- A wildfire in Northern California grew explosively Friday, forcing hundreds of people to evacuate from rural communities, destroying six homes, threatening thousands more, and prompting a state-of-emergency declaration from the governor.

"It's expanding like a balloon," state fire spokeswoman Nancy Longmore said. "It's moving very fast. There's many homes threatened.... This fire is extremely dangerous."

The fire that had only burned about a single square mile Thursday morning had surged to 101 square miles by Friday evening. It was 5 percent contained.

At one point, the blaze was bearing down on the 2,700 residents of San Andreas, prompting an evacuation order for the entire town 60 miles southeast of Sacramento. But the fire changed direction, and the order was called off a short time later, state fire spokesman Daniel Berlant said.

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"The fire was quickly approaching the community," Berlant said. "This fire is very dynamic and changing different directions with the topography.... That makes it very unpredictable, and with the exponential growth, we're seeing a lot of danger not only to residents in the path of this fire but to our own firefighters, as well."

San Andreas residents were told they still need to be prepared to evacuate.

Homes from smaller surrounding towns were under evacuation orders, with at least 460 people checking in at evacuation centers set up for the fire.

One of those evacuation centers was at the San Andreas Town Hall, which itself had to be evacuated for a while. "I had to move a kitchen full of food, 217 beds, three huge air conditioners," said Gina Gonzales, a Red Cross volunteer organizing the evacuation center.

About 90 minutes after moving everything to the Calaveras County Fairgrounds, Cal Fire ordered the evacuation center to move back to the San Andreas Town Hall because firefighters were going to make the fairgrounds their base camp, Gonzales said.

The roughly 65 evacuees were not only scared for their homes but frustrated with the moving and what they felt was a lack of information from fire crews, she said.

Six homes and two outbuildings burned Thursday, and 6,000 more were threatened, Longmore said. The number of homes burned could increase, as Longmore said the blaze was moving through rural areas with houses.

"The plan is to try to get this thing out," she said. "It's going to take quite a bit of work. We're in for the long haul here."

Firefighters were dealing with record heat and steep terrain as they tried to get the flames under control, CBS affiliate KOVR reported. Temperatures were expected to peak at 105 degrees according to the National Weather Service.

FEMA officials from the Region IX office in Oakland told CBS affiliate KPIX the fire threatened such destruction to constitute a major disaster. The funds will be used to cover expenses for field camps, equipment use, tools, materials, supplies, mobilization and demobilization activities.

Gov. Jerry Brown declared a state of emergency, helping to free up funding and resources in the firefight.

More than 1,500 firefighters, 178 engines, seven air tankers and 16 helicopters were assigned to fight the fire, which began Tuesday. The cause is under investigation.

Meanwhile another California wildfire threatened to sweep through an ancient grove of Giant Sequoia trees. The lightning-caused fire has charred 172 square miles and grew by nearly 40 square miles in the last week.

In a fight to save the trees, firefighters have been clearing lines with bulldozers around the Grant Grove and putting up sprinklers, said Andy Isolano, a spokesman for the Clovis Fire Department.

The grove is named for the towering General Grant tree that stands 268 feet tall. There are dozens of Sequoia groves in the Sierra Nevada, and some trees are 3,000 years old.

Fresno County Sheriff's deputies were going door to door Friday distributing mandatory evacuation notices to residents in the tiny community of Dunlap, east of Fresno. About 130 people live in Dunlap, but it wasn't clear how many residents will need to leave.

On Thursday, officials from Kings Canyon National Park ordered the evacuation of all Sequoia National Forest park visitors and park employees, concession staff and residents of Wilsonia in the Grant Grove area of the park.