The Telegraph Fire grew overnight, burning through 104,755 acres with containment down to 68%, fire authorities said during a community meeting late Monday.
The communities of El Capitan, Dripping Springs and Beverly Hills are being asked to evacuate immediately, according to the Telegraph Fire Information Facebook page.
The order was prompted after dry, windy conditions pushed smoke and flames through the area, eventually impacting state route 77.
As the blaze came down a hill toward the highway, crews worked to get ahead of it and keep it on one side, said Todd Abel, a fire operations chief with Central Arizona Fire.
“They were very successful until early this morning,” Abel said. “It did get across 77. We did … get aircraft in the air, and to try to catch this, what we call a slop over. It slopped over our containment line,” Abel said Monday.
The fire ignited June 4 about 100 miles east of Phoenix. The cause is under investigation. With the Mescal burning nearby, the area has been engulfed in recent weeks. The two combined have burned more than 175,000 acres.
The weather in the coming days could make firefighters’ jobs more difficult. The areas surrounding the fire are under excessive heat warnings until a heatwave eases Saturday, according to CNN meteorologist Michael Guy.
A monsoon will reach the area Tuesday, but along with the humidity that it will bring the area starved for rain, it could spark dry thunderstorms that fan existing flames, Guy said.
CNN’s Raja Razek and Aya Elamroussi contributed to this report.