California highway authorities reopened nearly all lanes of Interstate 5 in Southern California freeway Sunday as firefighters made progress on a wildfire.

The fire broke out Saturday afternoon in mountainous terrain near Castaic in northern Los Angeles County and grew to 450 acres, or more than half a square mile, prompting the California Highway Patrol to close a stretch of the busy freeway.

Two firefighters sustained burn injuries.

The fire remained completely uncontained, but firefighters were making “good progress” with the help of water-dropping helicopters and an aggressive ground attack, the U.S. Forest Service said.

Meanwhile, residents of a Northern California mountain town devastated by the huge Caldor Fire south of Lake Tahoe will be allowed back Sunday to inspect the damage. Most of Grizzly Flat’s homes, as well as the school, post office, church and fire station were destroyed in the first days of the fire.

Firefighters were diverted from battling the 342-square-mile (886 square kilometer) wildfire to fight multiple overnight lightning fires when thunderstorms swept across the state Thursday night into Friday.

The thunderstorms dropped light rain to slightly dampen the drought-stricken north, fire officials said.

Up to a half-inch of rain fell on portions of the Dixie Fire, which began in mid-July and has burned through huge swaths of the northern Sierra Nevada and southern Cascades. However, fire officials said the rain is drying fast and vegetation is becoming more flammable.

The second-largest fire in California history has burned 1,500 square miles (3,885 square kilometers) of land and more than 1,300 homes and other buildings. It was 65% contained.

(AP)