Firefighters are still working to control the wildfire in Shenandoah National Park. Right now the fire's spread to about 800 acres and it's 25 percent contained.
The heat and steep terrain are causing problems for the firefighters.
Each day begins with a two hour hike up to the fire.
"It makes it difficult because you're tired when you get up there," Bob Bury says.
That's because they're carrying about 35 pounds of equipment.
"That's about the heaviest part in there. Usually two water bottles is on your back, you have two more here you carry goggles, first aid gear, flashlight, compass, any extra stuff in there," Bury says.
Not to mention tools and in this heat, they're carrying double the water which could weigh up to 16 pounds.
"Most folks are putting down a gallon and a half to two gallons that's a lot of water, that's a lot of weight but at the end of the day those canteens are pretty empty." a firefighter says.
A second helicopter is being used to drop off firefighters to save their energy. But, the humidity is also taking a toll.
"It's really humid here in the east-it's dry in the west so you feel it a lot more in the east," Bury says.
Humidity can be dangerous if it's too high or too low, so, firefighters can monitor it in the field.
"Belt weather kit includes a thermometer, a device to measure humidity some other tools and a chart to mark it out. They really want to keep track of the relative humidity because it affects what the fire might do," Barb Stewart says.
It could be Saturday before these crews get a break.
"You get used to it-just keep plodding along," Bury says.
They're hoping to have the fire contained and begin backfiring Thursday. Officials haven't determined a cause.