The fire on Monday was still just 30 percent contained, state officials reported.
Smoke from a 7,000-acre brush fire in Monroe and Pike counties has settled over the Lehigh Valley, while flames have put 287 seasonal cabins at risk, the Pennsylvania Department of Conservation and Natural Resources reports.
At least four structures have already been destroyed, the Department of Forestry said, but no one has been injured since the 16-Mile Fire began Wednesday.
Pine Flats in Porter Township, Pike County, was evacuated over the weekend and the portion of Delaware State Forest bounded by Route 402, Highland Road, Pine Flats Road and Hobday Road was closed to the public, the state said. Visitors to the rest of the forest are asked to use "caution and discretion."
As of Monday, 135 people have been removed from the fire's path.
The closest community to the fire at the moment is Cresco, which is part of Barrett Township in Monroe County.
The Bear Town Fire, which also began Wednesday, was declared contained, the state said Sunday. The 16-Mile Fire is only 30 percent contained as of Monday, the state said.
Both fires were illegally and intentionally set, and the Bureau of Forestry has offered a $5,000 reward for information leading to an arrest or arrests. Those with information can call 717-362-1472 or 570-895-4000. The calls will remain confidential, the state said.
Low humidity, rugged terrain, changing wind directions and plenty of trees killed by gypsy moth infestation make the 16-Mile Fire difficult to control, the state said.
Department of Conservation and Natural Resources Secretary Cindy Adams Dunn was expected later Monday at the scene and was staying the night, the state said.
Dunn asked the Department of Environmental Protection to assist in monitoring the air in the Lehigh Valley. Northern Warren County has seen smoke and ash in recent days from the fire.
But Bobby Martrich, from Allentown-based Eastern PA Weather Authority, said while satellite images clearly show the fire, it looks like the smoke is blowing more toward Sussex County in New Jersey than Northampton County. The clouds visible in Easton and Allentown more likely are from an approaching weather system, which is coming in from the north-northwest, he added.
Rain is in the forecast for Tuesday -- which could help douse the fire -- but it likely won't be more than two-tenths of an inch in the fire zone, Martrich said. It will be less in the Lehigh Valley, he added.
There is the possibility of thunderstorms on Monday night and Tuesday afternoon, the National Weather Service said, and lightning in dry conditions could actually spark more fires.
Any drones in the fire area will be investigated and their violators prosecuted, DCNR spokesman Terry Brady said. There is heavy air traffic with tanker planes dropping water and flame retardant, especially near endangered buildings, he said.
Many of those battling the fires honed their skills fighting wildfires in the American West, the state said. There are also firefighters from other states, including a hotshot crew from New Mexico, battling the fire in the Poconos, the state said.
Tony Rhodin may be reached at arhodin@lehighvalleylive.com. Follow him on Twitter @TonyRhodin. Find lehighvalleylive.com on Facebook.