The American Fire burning near Foresthill is 60 percent contained, a drop from two days ago, but fire agencies reported the southern perimeter is now nearly secured.
The fire has burned 16,822 acres as of 10 a.m. Wednesday and is expected to be fully contained by Sept. 1.
Another portion of the fire on the northeast side is now a focus for containment, said Peter Frenzen, information officer for California Interagency Incident Management Team 4.
According to incident information website Inciweb.org, crews are continuing to mop up on the west and north sides of the fire to prevent fire from crossing established containment lines.
The primary fire activity is west of the Duncan Peak Lookout, where the blaze is being propelled by a mixture of clear air, wind direction that is moving up toward the valley and sun that heats the vegetation, Frenzen said.
“When things heat up, the wind goes up the valley in the day and down in the night,” Frenzen said.
“If you add an airflow in that direction, you get a fair amount of air moving through those canyons, and the fire moves.”
The fire teams have shifted strategy and moved control lines to the east because of the nature of the fire and topography, Frenzen said.
Aggressive fire suppression efforts have limited fire movement south to southwest along the North Fork of the Middle Fork of the American River, and efforts to contain the fire along the more difficult steep and hazardous terrain on the south and southeast perimeters continues with crews using direct fire attack methods where possible, according to Inciweb.org.
The fire teams have also set up additional indirect fire lines about 1,000 feet from the blaze to burn out the available vegetation, which acts as fuel for the fire.
“We are removing the fuel next to the fire line so when the fire gets there, it lays down the intensity and is safer for the firefighters and (creates) a greater probability of securing it,” Frenzen said.
These fire lines are typically created in the early morning and evening, which causes additional smoke and ash during those times and should not alarm people, Frenzen said.
Four structures have been damaged by the fire, Frenzen said, and some structures have been wrapped in fireproof material with a reflective surface that repels heat.
Mosquito Ridge Road is closed from the junction of Ralston Ridge Road to the junction of the Duncan Diversion Dam access road west of French Meadows Reservoir. Foresthill Road is closed from Humbug Canyon Road to Robinson Flat Campground, and Forest Road 43 is closed from Robinson Flat Campground to Mosquito Ridge Road.
Robinson Flat Campground and Duncan Peak Lookout remain closed, and the French Meadow Reservoir and access to the Oxbow Middle Fork American Rafting Launch remain open.
For smoke information, visit http://placer.ca.gov/apcd
To contact Staff Writer Jennifer Terman, email firstname.lastname@example.org or call 530-477-4230.