Mariposa evacuated as wildfire near Yosemite grows to 25,000 acres

A wildfire ravaging the area west of Yosemite National Park grew to 25,000 acres Tuesday, more than tripling in size in one day and causing evacuations in the area, including the town of Mariposa, officials said.

Firefighters dealing with steep terrain and dry weather said the blaze was only 5 percent contained.

The Detwiler Fire started about 4 p.m. Sunday in Mariposa County and grew from 7,100 acres on Monday to 25,000 acres by Tuesday night, officials with the California Department of Forestry and Fire Protection said.

Firefighters from the Stanislaus Consolidated Fire Protection District arrive to fight the Detwiler Fire on Monday July 18, 2017. Firefighters from the Stanislaus Consolidated Fire Protection District arrive to fight the Detwiler Fire on Monday July 18, 2017. Photo: Stanislaus Consolidated Fire Dist. Photo: Stanislaus Consolidated Fire Dist. Image 1 of / 58 Caption Close Mariposa evacuated as wildfire near Yosemite grows to 25,000 acres 1 / 58 Back to Gallery

The fire has destroyed eight structures and damaged another. The inferno was threatening 1,500 other structures as it continued to burn, Cal Fire said.

The town of Mariposa was evacuated, and a number of nearby roads were closed, affecting thousands of people.

Highway 140 at Agua Fria, a route leading to Yosemite, was shut down Tuesday afternoon.

An evacuation center was open at Mariposa Elementary School.

The blaze was coming dangerously close to electrical lines that supply power to Yosemite National Park, according to officials.

Aircraft and more than 1,400 firefighters were battling the blaze, and investigators were still working to determine a cause.

Sarah Ravani is a San Francisco Chronicle staff writer. Email: sravani@sfchronicle.com Twitter: @SarRavani