The Shady Fire in the Frank Church River of No Return Wilderness area has burned over 3,600 acres since it was started by lightning on July 10.
Officials say they have 23 personnel working on the fire, along with two engines.
Fire activity picked up on Saturday and the Shady Fire started moving northeast, towards Duffield Creek, according to officials.
Firefighters cannot directly fight the fire due to active fire behavior, heavy fuel loading and presence of multiple snags, officials say.
Incoming thunderstorms are predicted for Monday, which will bring gusty and erratic winds and will continue a hot and dry trend in the area.
Fire officials say there no fire restrictions at this time but still urge people to pour water and add dirt to their campfires until it is cold to the touch.
