In this photo provided by the U.S. Forest Service, fire crew members stand watch near a controlled burn operation as they release a very pistol, as they fight the Rim Fire near Yosemite National Park in California, Monday, Sept. 2, 2013.
Update 11:33 a.m. Rim Fire may continue to grow due to low humidity, other conditions
The Rim wildfire that began three weeks ago today is now 80 percent contained, officials say, but it has burned more than a quarter of a million acres, and it may continue to grow, thanks to low humidity and other conditions.
More than 3,400 people have helped fight the blaze, the U.S. Forest Service says in its latest status update. Air quality concerns have led to warnings hundreds of miles away, according to NBC News. Officials say a shift in wind direction could help clear out the smoke on Monday.
Reporting from Modesto, Calif., Bob Hensley tells NPR's Newscast unit that the Rim blaze has torched 385 square miles, making it the third-largest wildfire in California's history:
"Officials say it could take a few more weeks for total containment. The weekend weather forecast, calling high temperatures and low humidity levels, could contribute to even further growth.
"Despite its wide scope, the Rim Fire is far from becoming the worst in California history. That distinction goes to the so-called Cedar wildfire, which swept through 427 square miles of San Diego County 10 years ago. The blaze destroyed 2,800 buildings and resulted in the deaths of 14 people.
"Investigators say both the Cedar and now the Rim Fire were started by careless hunters."
Officials on Friday reopened a portion of State Route 120 to traffic, from Groveland, Calif., to Yosemite National Park, but many other access roads remain closed. You can keep an eye on the Rim Fire and other blazes at KPCC's Fire Tracker service.
Previously: As firefighters continue to battle a gigantic wildfire in and around Yosemite National Park, environmental scientists are already moving in looking to protect habitat and waterways ahead of the fall rainy season.
Members of the federal Burned Area Emergency Response team will begin hiking the rugged Sierra Nevada terrain this weekend to identify areas at the highest risk for erosion into streams, the Tuolumne River and the Hetch Hetchy Reservoir, which provides San Francisco's famously pure water.
The wildfire now ranks as the third largest fire in California history, having burned 385 square miles of timber, meadows and sensitive wildlife habitat. It started Aug. 17 when a hunter's illegal fire swept out of control.
It has cost $81 million to fight the fire, and officials say it will cost tens of millions of dollars more to repair the environmental damage.
This story has been updated.