Flames rise behind a vacant house as firefighters work to halt the Detwiler fire near Mariposa, Calif., Wednesday, July 19, 2017. (AP Photo/Noah Berger)

Flames rise behind a vacant house as a firefighter works to halt the Detwiler wildfire near Mariposa, Calif., on Wednesday, July 19, 2017. As wildfires rage throughout the western U.S., one California blaze in the rugged mountains outside of Yosemite National Park forced thousands of nearby residents to flee their homes. (AP Photo/Noah Berger)

Flames rise behind a vacant house as a firefighter works to halt the Detwiler fire near Mariposa, Calif., on Wednesday, July 19, 2017. (AP Photo/Noah Berger)

An air tanker drops retardant while battling a wildfire fire near Mariposa, Calif., on Wednesday, July 19, 2017. According to fire officials, the blaze has scorched more than thousands of acres and destroyed multiple structures. (AP Photo/Noah Berger)

An air tanker drops retardant while battling a wildfire near Mariposa, Calif., Wednesday, July 19, 2017. The fire has forced thousands of people from homes in and around a half-dozen small communities, officials said. (AP Photo/Noah Berger)

An air tanker drops retardant while battling a wildfire near Mariposa, Calif., on Wednesday, July 19, 2017. The fire has forced thousands of people from homes in and around a half-dozen small communities, officials said. (AP Photo/Noah Berger)

These Tuesday, July 18, 2017, webcam photos provided by the Yosemite Conservancy show the monolith known as Half Dome as smoke from the Ditwiler fire swirls into Yosemite Valley, from late morning to early afternoon, in Yosemite National Park, Calif. The Northern California blaze is also threatening powerlines that provide electricity to the park, officials said. The park remained open Wednesday but several roads frequented by tourists were closed. (Webcam by Yosemite Conservancy at yosemiteconservancy.org via AP)

A burned structure stands atop a hill on Yaqui Gulch Road as a wildfire burns near Mariposa, Calif., on Wednesday, July 19, 2017. According to fire officials, the blaze has scorched thousands of acres and destroyed multiple structures. (AP Photo/Noah Berger)

A chimney stands at a burned residence on Yaqui Gulch Road as a wildfire burns near Mariposa, Calif., on Wednesday, July 19, 2017. The fire has forced thousands of people from homes in and around a half-dozen small communities, officials said. (AP Photo/Noah Berger)

A chimney stands at a burned residence as the Detwiler fire burns near Mariposa, Calif., Wednesday, July 19, 2017. (AP Photo/Noah Berger)

A chimney stands at a burned residence on Yaqui Gulch Road as a wildfire burns near Mariposa, Calif., on Wednesday, July 19, 2017. The fire has forced more than 4,000 people from homes in and around a half-dozen small communities, officials said (AP Photo/Noah Berger)

A trellis rests in front of a Hummingbird Lane residence leveled by the Detwiler fire near Mariposa, Calif., on Wednesday, July 19, 2017. A surging wildfire raced through California mountains and foothills west of Yosemite National Park on Wednesday, forcing thousands to flee tiny, Gold Rush-era towns and wafting smoky haze over the park’s landmark Half Dome rock face. (AP Photo/Noah Berger)

Melted lawn chairs rest outside a residence leveled by the Detwiler fire near Mariposa, Calif., on Wednesday, July 19, 2017. A surging wildfire raced through California mountains and foothills west of Yosemite National Park on Wednesday, forcing thousands to flee tiny, Gold Rush-era towns. (AP Photo/Noah Berger)

A scorched car rests next to a residence leveled by the Detwiler fire near Mariposa, Calif., on Wednesday, July 19, 2017. A surging wildfire raced through California mountains and foothills west of Yosemite National Park on Wednesday, forcing thousands to flee tiny, Gold Rush-era towns. (AP Photo/Noah Berger)