California wildfire at 80 percent containment as some evacuations lifted

Crews battling a massive California wildfire near Yosemite National Park made significant gains Tuesday, boosting containment up to 80 percent, as officials lifted evacuation orders and advisories that had loomed over several Sierra Nevada communities.

Aided by higher humidity and lower temperatures, firefighters tightened their grip on the massive blaze, squashing out flames on its northwestern and southwestern flanks, said Andrea Capps, a spokeswoman for the multiagency fire management team.

And yet, Capps added, "there's still a lot of work to be done" as firefighters face down thick plumes of smoke and aggressive flames.

Meanwhile, sheriff's offices in Tuolumne and Mariposa counties dropped evacuation advisories for communities in the fire's path, according to the Associated Press — suggesting that some anxieties in the region had eased.

Officials are still investigating the cause of the so-called Rim Fire, which sparked Aug. 17 in neighboring Stanislaus National Forest.

The blaze now spans over 368 square miles, or 235,841 acres, making it the fourth-largest blaze in modern California history. It surpasses a 1932 fire in Ventura County, according to officials.

The fire threatens some 4,500 homes, although many of those structures are "not in imminent danger," said Dan Bastion, a spokesman for the Rim Fire command center. Some 11 residences have already burned down, according to the California Department of Forestry and Fire Protection.

Authorities are investigating the cause of the blaze, but the possibility that it was started by an illegal marijuana growing operation was recently raised by a fire chief in Tuolomne County.

Elisha Fieldstadt of NBC News and The Associated Press contributed to this report.