After the enormous Rim Fire ambushed the area in and around Yosemite National Park over the last week and a half, firefighters are finally starting to get a handle on the blaze and are eyeing full containment within two weeks.
The fire burned about 300 acres an hour on average during the 24-hour span ending Wednesday evening, down from 1,000 acres an hour the day before. It spread 10 times faster, burning more than 3,000 acres an hour, during its peak last week.
About 4,500 firefighters had the largest fire in the nation 30 percent contained, significantly up from 20 percent a day before. Full containment is now expected by Sept. 10.
"A lot of that has to do with the fact that the weather is cooperating a lot more with us," said Cal Fire spokesman Daniel Berlant, noting temperatures have cooled and humidity has risen.
Berlant said the constant air drops and bulldozer-dug dirt lines around the perimeter of the fire have paid off.
"There's a lot of work that's been done over the past week and a half now to really put this fire to bed," Berlant said. "We are hoping that we've turned the corner."
Also on Wednesday, the California National Guard said it had launched an unmanned aircraft typically used in combat operations in Afghanistan and Iraq to fly over the fire. The drone isn't directly fighting the fire, but rather gathering information that firefighters on the ground can use to know where to go.
"It gives them a great amount of insight and information as far as understanding where the fire is most intense and how they can best approach it," said Capt. Will Martin of the California National Guard. "That's an advantage we don't have as far as being able to fly (human-operated aircraft) into the more dangerous areas of the fire."
The drone took off on Tuesday night from the March Air Reserve Base in Riverside, where it is being operated remotely. Although it has been used recently on other major wildfires, the domestic use for the MQ-1 "remotely-piloted aircraft" has been limited, and the National Guard is hoping to expand its role.
The fire became the sixth-largest wildfire in recorded California history Wednesday night when it grew to nearly 192,500 acres -- slightly more than 300 square miles -- surpassing the Klamath Theater Complex fire of 2008. The fire had scorched 187,000 acres as of Wednesday morning, up from 184,000 a night before and 179,000 on Tuesday morning.
The fire had spread into a small portion of Yosemite and reached the Hetch Hetchy watershed inside the park, the source of water for 2.6 million residents and businesses in the Bay Area, though water quality remains unaffected.
By Wednesday, the fire had stretched three-fourths of a mile past O'Shaughnessy Dam to the south and east, next to the Hetch Hetchy Reservoir where drinking water is stored. Firefighters are working to protect the infrastructure from the blaze as ash falls on the surface of the water.
Since the fire began on Aug. 17, small communities in Tuolumne County have been advised to evacuate, roads in and around the park have closed, a Berkeley-run Sierra family camp was destroyed, San Jose's family camp was damaged and giant sequoia trees have been threatened. Three firefighters had suffered minor injuries through Tuesday, with a fourth non-life-threatening injury reported on Wednesday. Structures destroyed remained at 111 while the cost to fight the fire has hit $39 million. The cause of the Rim Fire remains under investigation.
Contact Mike Rosenberg at 408-920-5705. Follow him at Twitter.com/RosenbergMerc.