Nearly 3,800 firefighters contained 20 percent of the Rim Fire that has ravaged nearly 180,000 acres near Yosemite National Park in California by Tuesday morning, reported KCRA-TV.
Rapid growth, dry fuels and high winds have taken a toll on suppression efforts, according to an incident report. Fire crews were working to control a spot fire in the southeast portion as it crossed Highway 120, causing mandatory evacuations. The cause of the blaze, which began on August 17, is still unknown.
Steep, inaccessible terrain remains a concern for crews. Aviation methods, relying on Modular Airborne FireFighting Systems and DC-10 air tankers have been instrumental in helping contain the fire.
The blaze has grown within a mile of the Hetch Hetchy Reservoir, which supplies 85 percent of the drinking water for 2.4 million people in San Francisco and several counties in the Bay Area. The San Francisco Public Utilities Commission reported no change or impact on water quality or delivery on Monday.
Should the fire contaminate Hetch Hetchy, consumers can rely on reserves in Bay Area reservoirs such as San Antonio and Crystal Springs. However, two of the three hydroelectric power generators have been out of commission since August 19 due to damage from the Rim Fire, costing the SFPUC $600,000 for additional power supplies.
There are currently 33 active, uncontained fires in the West, according to the National Interagency Fire Center. So far this year, 33,324 wildfires have burned more than 3.5 million acres, roughly 60 percent of the 53,884 10-year average.
The cost to fight the Rim Fire has jumped to $27.2 million, up from $20.1 million on Monday. It is now the seventh largest wildfire in California history.