Inaccessible terrain and dry conditions continued to thwart nearly 3,500 personnel over the weekend in their efforts to extinguish the Rim Fire in Yosemite National Park in California, which has grown to 143,980 acres, according to the National Interagency Fire Center.
Firefighters had only contained 7 percent of the Rim Fire by Monday morning, as it continued to grow on the northeast and eastern park areas, according to an incident report. Yosemite spokesman Tom Medema told the Associated Press that the blaze was edging closer to the Hetch Hetchy Reservoir, which provides drinking water to 2.4 million people in San Francisco as well as in Santa Clara, Alameda and San Mateo counties.
USA Today reported an incident commander flew near the Hetch Hetchy area Sunday morning in an effort to evaluate the reservoir's state. Heavy smoke veiled the area, disabling the crew from making a clear assessment.
San Francisco Public Utilities Commission reported no change or impact in water quality or delivery from Hetch Hetchy in a statement released Sunday. Should the Rim Fire interrupt water delivery from Hetch Hetchy, SFPUC can utilize reserves in Bay Area reservoirs, such as San Antonio and Crystal Springs.
However, Supplemental power supplies have cost the SFPUC about $600,000 since Aug. 19. Two of the system's three hydroelectric powerhouses have not been in use since then, and the difference has been made up by accessing power from an existing power bank and purchasing power on the open market.
Firefighters have been using Modular Airborne FireFighting Systems and air tankers to preemptively suppress the Rim Fire's potential spread toward the Highway 108 corridor along the eastern edge.
The Rim Fire, which reportedly started on Aug. 17, is one of many wildfires plaguing the West. Investigators are currently working to discover a cause for the Yosemite wildfire. Firefighters were able to contain six fires on Saturday, according to the NIFC, bringing the total number of active wildfires down to 36 from more than 50 on Friday. The cost to fight the Rim Fire jumped from $12.4 million on Sunday to $20.1 million Monday.
More than 33,000 wildfires have burned through 3.5 million acres so far this year, 60 percent of the nationwide 10-year average. The Rim Fire is the 14th largest wildfire in California history.