Firefighters capitalized on a blanket of moist air that settled over the mountains near Yosemite National Park on Tuesday night to increase containment of the Rim fire to 23%.
The blaze – now entering its 12th day – has burned 187,466 acres and is on pace to soon become the sixth-largest fire in state history. Containment was up from 20% Tuesday.
Overnight, firefighters continued to build and strengthen containment lines and conduct backfiring operations to slow the blaze as it rages farther into Yosemite National Park.
Authorities also ordered evacuations for residents in the fire's path south of California 120 and north of Old Yosemite Road.
The U.S. Forest Service said Tuesday that ground crews planned to work through the night to build containment lines on the northern flank of the fire. Communities north of the blaze, along the Highway 108 corridor from Tuolumne City to Pinecrest, also remained under evacuation orders.
Officials said crews on the southeast flank in Yosemite were planning to conduct extensive backfires, a dangerous tactic in which firefighters burn vegetation inside a fire line to help contain a rapidly spreading blaze.
Nearly 4,100 firefighters are taking part in the effort.
The blaze has destroyed 111 buildings, including 31 homes, and was the seventh-largest fire in California history. The fire was spewing out huge clouds of smoke that drifted into Nevada. The blaze had spread across 281 square miles.
The Rim fire, said California Department of Forestry and Fire Protection spokesman Daniel Berlant, was "burning its way into the record books."
A number of structures were lost in the Tuolumne Berkeley Family Camp, which includes three commercial properties and 85 tent cabins and outbuildings, the Forest Service said.
While firefighters have used the Tuolumne River and granite formations on the fire's northern edges to set up defenses, crews have found little to work with on the blaze's eastern front south of the Hetch Hetchy reservoir.
"They're in scouting mode," Dick Fleishman of the U.S. Forest Service said of fire crews. "There's not a lot of real good areas to get out in there and do a lot of work."
The Stanislaus National Forest is taking the brunt of the blaze, with the Groveland Ranger District making up most of the southern flank. The region has been hit hard by fires in the past, the most significant in 1987, which claimed the life of a firefighter.
This week's fire has brought sorrow among the district's employees, who not only recall the past devastation but also begrudge the current damage. The fire burned though an area that had a pending $1-million timber sale, said Maggie Dowd, district ranger in the Groveland Ranger District.
"The economic impacts are real, but we haven't begun to estimate them yet," Dowd said Tuesday from her office in a building shrouded in smoke.