Updated

Firefighters gained ground Monday on a wildfire along the northern edge of Los Angeles County that temporarily closed a major freeway and knocked out electricity to more than 4,000 homes, authorities said.

The blaze had scorched more than 6 square miles, or 4,000 acres, of hillside, fire dispatchers said, and was 60 percent contained.

Winds up to 15 mph blew the flames in the direction of Frazier Park, a community of about 2,200 residents, but authorities said no homes were immediately threatened. Two outbuildings were damaged.

The blaze broke out Sunday and damaged a Southern California Edison substation and at least six power lines, company spokesman Jeremy Rawitch said. By Sunday night, power was restored to all but 75 customers, Rawitch said.

The fire also forced the partial closure of Interstate 5 for more than three hours. The cause was under investigation.

One firefighter was treated for heat exhaustion, officials said.

A second wildfire northeast of San Jacinto in Riverside County burned more than 300 acres of steep mountainous terrain and was contained, said Captain Julie Hutchinson with the California Department of Forestry. It had been sparked by fireworks Saturday, Hutchinson said.

Also, federal authorities arrived in central Idaho on Monday to investigate a helicopter crash a day earlier that killed a pilot and three firefighters on a wildfire mission in the Payette National Forest. Fire crews in the area have been working to protect the cabin community of Yellow Pine from an 11-square-mile complex of fires.

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