The Power Fire near Beardsley Reservoir, entering its fourth day, has burned nearly 900 acres of brush and trees.
Firefighters as of this morning had formed a containment line around 32 percent of the fire, burning along the Middle Fork Stanislaus River canyon's south side.
Today, at least 447 firefighters will continue working on the blaze, which had consumed 881 acres as of this morning, said Bob Poole, U.S. Forest Service fire information officer.
The firefighting efforts have been aided by favorable weather.
Yesterday brought cooler temperatures, higher humidity and gentler winds and more of the same is expected this week, Poole said.
Late last night, the Forest Service said in a prepared statement that 100 homes could eventually be threatened in the communities of Bumblebee, Leland Creek and Cow Creek.
The homes, however, are not in the direction of the fire's spread and not imminently threatened, Poole said.
The warning is given for the utmost caution, and because "you never know exactly what will happen in a day," he said.
No evacuations have been called and are not expected to be.
All roads are open. The Forest Service, however, asks the public to avoid forest road 5N95 at Beardsley Road to ease traffic for fire equipment.
Smoke should be less of a factor, too, he said. He hasn't seen or smelled any since Tuesday at the operational camp set up at Dodge Ridge Ski Area.
The fire started around forest road 5N95 very near to the Donnell powerhouse, on the east bank of the Middle Fork Stanislaus River, upriver of Beardsley Reservoir, around 5:30 a.m. Monday.
It grew from one to four acres to about 100 acres within five hours, as it spread up the river canyon.
No cause has been determined.