MARIPOSA -- Firefighters were stretched thin Saturday night after a second wildfire broke out in Mariposa County, not far from where firefighters were trying to corral a blaze that started Friday evening near Midpines, according to the California Department of Forestry and Fire Protection.
As of Saturday night, the Telegraph fire had burned about 16,000 acres and was threatening 2,000 homes in Midpines, the city of Mariposa, Greeley Hill, Coulterville, Bear Valley and Mount Bullion Camp, according to Cal Fire.
Daniel Berlant, a Cal Fire spokesman, said the Telegraph fire grew from 1,000 to 16,000 acres, or 25 square miles, from Saturday morning to the evening.
"Any fire we have this time of year is extremely active," he said. "The erratic behavior is because there is so much fuel out there to burn."
The Telegraph fire, which is about 30 miles west of Yosemite Valley, forced the evacuations of 170 homes Saturday, according to fire officials.
State fire spokeswoman Karen Guillemin said most of the evacuated homes are in Midpines but that residents in other small towns are being asked to prepare to leave the area.
Midpines is along Highway 140, the thoroughfare that leads to the west entrance of Yosemite National Park.
Guillemin said the cause of the Telegraph fire "is definitely target shooting," but would not elaborate.
The fire also forced officials to cut power to Yosemite National Park, and it had not been restored Saturday night.
Guillemin said the weather was not helping firefighters Saturday, with temperatures of higher than 100 degrees and low humidity.
"Dozers are trying to push dirt as fast as they can to get safety zones for our firefighters that are out there," Guillemin said. "Crews are cutting brush as fast as they can, but it's an extremely dangerous situation at this point."
The blaze started about 3 p.m. Friday in the area of Telegraph and Sherlock roads and burned heavy vegetation in the steep Merced River canyon about 40 miles northeast of Merced. Firefighters had 5 percent of the blaze contained Saturday, but that dropped to 0 percent containment Saturday night.
Firefighters were scrambling to handle the second wildfire that started Saturday on Mount Bullion, said Wayne Barringer, a Cal Fire spokesman.
"We had no idea a second fire would break out in the same area," Barringer said.
Both fires were burning between Highways 140 and 49 and north of the city of Mariposa. Barringer did not have any more information about the Mount Bullion fire.
He said the Telegraph fire was burning south on both sides of the Merced River at a moderate to rapid rate of speed. The rocky, isolated terrain was creating access problems for firefighters.
The fire had drawn 884 firefighters, eight aircraft, 94 engines, 20 hand crews, three water tenders and 24 bulldozers, Cal Fire reported.
The California National Guard planned to send two Black Hawk helicopters today, Guard Capt. Al Bosco said. The helicopters are equipped with 660-gallon water buckets and can carry firefighters and equipment to the fires, he said.
The Black Hawk crews are from the Louisiana National Guard and were sent to California to help with the more than 2,000 fires sparked by a massive lightning storm June 21.
A California-based Fire Hawk helicopter with a 1,000-gallon water tank also was tentatively scheduled to join the Telegraph fire, Bosco said.
The fire had not damaged any structures. Sheriff's officials notified residents Saturday to be ready to evacuate if the flames got too close to their homes.