An excessive heat warning was issued Saturday for Southern California’s inland and desert communities, with triple-digit temperatures forecast through next week, bringing an elevated fire risk to some areas, according to the National Weather Service.

Portions of Los Angeles County, including Palmdale and Lancaster, as well as smaller towns in the San Gabriel Mountains and the Antelope Valley, can expect to see temperatures of 100 to 110 degrees. The warning is in effect through 10 p.m. Wednesday.

Heat warnings were also issued for mountain areas of Ventura and Santa Barbara counties, and for desert communities in the Inland Empire such as Victorville and Apple Valley.

In the Central Valley, high winds and dry conditions have added to worries of fires. Pacific Gas and Electric said thousands of customers, mainly in the Fresno area but also Sacramento and Bakersfield, could lose electricity on Saturday in a power shutoff plan to prevent wildfires.

In L.A. County, Angeles National Forest has been a particular area of fire concern.

On Friday afternoon, a wildfire broke out in the Fork area of the forest and has since spread to 330 acres. More than 200 personnel from federal, state and county agencies were on the scene Saturday battling the fire with “lots of air tankers and helicopters,” said Angeles National Forest spokeswoman Dana Dierkes.

The Fork wildfire was “0%” contained as of Saturday morning, she said. “Vegetation is very dry, it’s been very hot,” Dierkes said, adding that officials hoped to extinguish the blaze as quickly as possible.

Two people were treated for potential smoke inhalation, Dierkes said, and recreationists were evacuated from the East Fork of the San Gabriel River and from the parking lot area at the East Fork Trailhead. Residents have not been evacuated at this time.

The East Fork area is a popular destination for hiking and camping, and many have been going there to cool off from the hot weather in L.A. But those looking to access the river through East Fork will find the road has been closed so crews and equipment can have a clear path to fight the fire.

Farther east, closer to where Angeles National Forest meets the San Bernardino National Forest, some 300 firefighters are still battling the Vista wildfire, which has scorched almost 3,000 acres on the south side of Lytle Creek. As of Saturday morning, that fire was reported as 83% contained, according to the interagency information website InciWeb.

Between July 1 and July 11, there have been 38 wildfires within and surrounding Angeles National Forest, Dierkes said.

Separately, a fire ignited Friday afternoon in Palmdale located north of East Avenue Q & 35th Street East. The so-called Deer fire, affecting about 270 acres, has been fully contained, according to California officials.