(CNN) -- A fast-moving wildfire in southern New Jersey has grown to nearly 4,000 acres less than 24 hours after it started.
The Jimmy's Waterhole Fire was 50% contained and had burned 3,859 acres as of Wednesday morning, officials said. It was just 500 acres at 10 p.m. Tuesday, according to the New Jersey Forest Fire Service.
About 170 structures in the Manchester Township area were evacuated Tuesday night, but all residents have since been allowed to return home, Manchester Police Chief Robert Dolan said during a news conference Wednesday.
No structures are damaged and no injuries have been reported, officials said, but firefighters have faced "extreme fire behavior," said John Cecil, the assistant commissioner of state parks, forests and historic sites at the New Jersey Department of Environmental Protection.
"We saw a wall of fire, 200-foot flames, raining fire embers. I don't mean to be dramatic, but this was a severe situation that these guys and gals managed to keep in place and protect lives and property. And for that, we cannot thank them enough," Cecil said.
The fire was primarily burning on federal, state and private property in Manchester Township, but it had jumped to the nearby borough of Lakehurst.
The cause of the fire is under investigation, New Jersey Forest Fire Service Warden Trevor Raynor said.
"Unfortunately, the weather won't be providing much help today. More warm, dry, and breezy conditions are expected. Next chance for rain is the weekend," the National Weather Service in Mount Holly, New Jersey, said.
There's an elevated risk for wildfire spread across New Jersey and Delaware on Wednesday, with sustained winds up to 15 mph and gusts up to 25 mph expected. Low humidity and dry fuels are also contributing to the risk.
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