This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

A huge wildfire near Yosemite National Park swelled to more than 70,000 acres overnight as flames destroyed dozens of structures and forced two towns to evacuate.

Fire retardant is dropped on a side of a hill near Mariposa, Calif. (Credit: Marcus Yam / Los Angeles Times)

Burning east of Merced, the Detwiler fire in Mariposa County grew from 48,000 acres to 70,096 acres Thursday morning, said Nancy Phillipe, spokeswoman for the California Department Forestry and Fire Protection.

The aggressive blaze, which was 10% contained, has forced more than 4,000 residents to flee their homes and triggered evacuations for the historic gold rush towns of Mariposa and Coulterville. The massive fire has destroyed 45 structures and damaged six others, she said.

More than 3,100 firefighters tackled 2- to 4-foot flames, and observed some flares up to 25 feet tall, said Jeff Marshall, a fire behavior analyst with the Cal Fire Incident Management.

Read the full story on LATimes.com.