The fire has engulfed 70,800 acres (28,700 hectares) since Wednesday, and more than 600 personnel and 40 fire engines have been deployed to contain it, Cal Fire, the state’s fire service, said in an update on Friday.

The fire sparked in the Los Padres National Forest in San Luis Obispo County and was growing exponentially, officials warned. The area is mostly uninhabited.

A fast-moving California wildfire exploded to become the state’s biggest of the year, forcing evacuations and the closure of a highway, and evoking memories of the devastating blazes that laid waste to parts of the state in January.

A wildfire in a wilderness area on the Central California coast grew to more than 70,800 acres Friday as the fire-prone state enters the hot and dry months of summer. The Madre Fire, burning in warm conditions in San Luis Obispo County,

The Madre fire has grown to 70,800 acres in San Luis Obispo County, making it the largest blaze in the state this year.