Evacuation orders were lifted late Wednesday as crews made progress in battling the Grand fire in Chino Hills, fire officials said.
The vegetation fire ignited near Grand Avenue Park around 7 p.m.
An hour later, the blaze had burned 30 acres, prompting officials to urge residents living on Mill Stream Drive, Falling Star Lane, Valley View Lane and Sweet Grass Lane to leave their homes immediately.
One firefighter suffered a minor injury and was transported to a hospital, according to Cal Fire.
Chino Valley Fire reported shortly before 8 p.m. that the blaze had the potential to spread to 200 acres and was threatening structures. Ground crews and water-dropping helicopters worked to get a handle on the blaze.
By 9:30 p.m., officials reported that the fire was holding at 30 acres amid more favorable conditions — cooler nighttime temperatures and higher humidity.
Around 10 p.m., all evacuation orders and warnings had been lifted and all aircraft released, officials said. Grand Avenue between Grand Avenue Park and the city limit remained closed until further notice.
The National Weather Service warned Wednesday that moderate to locally strong winds and low humidity would elevate the risk of fire in inland areas of L.A. County this week. Chino Hills is just to the east of the L.A. County border.
The highest risk of fire weather is currently expected on Saturday and Sunday, when winds of 15 to 30 mph are expected, with isolated gusts up to 50 mph.
