Firefighters this morning worked to bring the Power Fire near Beardsley Reservoir closer to containment as it continued moderate growth northeast and reached 925 acres.
The containment estimate was upped to 40 percent Thursday night as more resources were devoted to the wildfire. The number of personnel in the fight is now 565, up from 447 yesterday.
Eighteen hand crews, 36 engines, five helicopters, four airplanes, 11 water tenders and three bulldozers are fighting the fire.
"Significant inroads were made in containment," said Bob Poole, U.S. Forest Service fire information officer.
The fire's growth potential remains high in the dry wooded area of the Middle Fork Stanislaus River.
But "everything right now seems to be in our favor," Poole said, "except the terrain."
The terrain is described as extremely difficult, with firefighters facing strenuous hikes to the fire line.
Dropping temperatures and rising humidity since Wednesday have helped slow the fire.
There are 100 homes in nearby locations that could be threatened, but are not imminently in danger, as the fire is not moving in their direction, Poole said.
Also, there is obviously less smoke which means less heat inside the fire, he said.
The Forest Service said that weekend recreational activity should not be impacted by smoke or road closures.
Fire personnel and equipment will be on the roads, however.
The fire was reported early Monday morning near the Donnell powerhouse, just upriver from Beardsley Reservoir, and quickly spread up the southeast river canyon to burn over 100 acres.