FORBESTOWN, Calif. — A wildfire that threatened about 70 homes in rural Butte County more than doubled in size Tuesday when firefighters had to briefly retreat from unpredictable winds unleashed by passing thunderclouds, California fire officials said.

The loss of valuable firefighting time allowed the two-day-old blaze in the picturesque Feather Falls area to grow from 1,000 acres in the early afternoon to more than 2,500 acres by evening, and its containment level to drop from 30 percent to 20 percent, said Anthony Brown, a spokesman for the California Department of Forestry and Fire Protection.

“All the work of the fire crews came to a cease because of safety reasons,” Brown said. “When they retreated, it allowed the fire to consume a bigger area.”

Lightning from the passing storm front also started a few fires in the Inyo National Forest, including one that burned about 100 acres near Bishop before fire crews stopped its spread, said Carrie McDivitt, a forest dispatcher.

The Bishop fire was about 40 miles southeast of Mammoth Lakes, where elsewhere in the Inyo National Forest firefighters were still trying to contain a 347-acre fire. The nearest structures were at a campground about 2.5 miles away from the flames, but no evacuations were ordered.

Smoke diminished throughout the day as crews established containment lines around the blaze, said fire spokesman Matt Corelli. The fire was 57 percent contained Wednesday morning. Corelli said the cause of the fire was human-caused and was under investigation by the U.S. Forest Service.

Firefighters there were hoping thunderstorms forecast for later Wednesday would bring more rain than lightning.

Meanwhile, a wildfire outside of Yosemite National Park that was started July 25 by a person taking target shooting practice was nearly completely contained by Tuesday evening. The fire has destroyed at least 28 homes, consumed about 34,000 acres west of Yosemite and cost nearly $37 million to fight, and state fire officials are investigating whether the individual should be prosecuted.

The expanding blaze in Butte County led to the evacuation of residents living between the middle and southern forks of the Feather River, which feeds into Lake Oroville, and prompted officials to push back their prediction for when the fire would be surrounded from Wednesday to Sunday.

Brown said the region’s temperatures were expected to reach the triple digits on Wednesday, which could further delay progress in containing the fire.