SAN FRANCISCO--As the massive Rim Fire near Yosemite National Park continues to grow, firefighters are scrambling to get a hand on the blaze before it takes out San Francisco's water and power.
Though the metropolis is nearly 150 miles away from the fire, the blaze threatens the Hetch Hetchy Regional Water System, which provides the San Francisco Bay Area with 85 percent of its water and 20 percent of its power. On Tuesday the blaze reached the edge of Hetch Hetchy Reservoir--a primary part of the system.
According to San Francisco Public Utilities Commission Communications Director Charles Sheehan, the threat is not the fire itself, but the ash it creates, which has been showering the area like snowfall for several days.
"The facilities are very fire resistant," Sheehan told HuffPost. "The concern is ash deposition in the reservoir and how that might affect the water quality."
Sheehan noted that, as of Tuesday, there was no change in the water.
"We're continuing to deliver as usual, we're just increasing our monitoring," he said, adding that the commission could switch to a reserve system if needed. Because of recent improvements to the system, officials could reroute water earmarked for other uses to San Francisco.
"If we do get to a point where we need to switch to reserves, we have several months available," said Sheehan.
While the water may be safe, the fire has, however, affected two of the system's hydroelectric powerhouses, forcing them offline. As of Monday, San Francisco had already purchased $600,000 of energy on the open market to make up for the loss.
Officials said a disruption of power or water would be highly unlikely, but Kelly Huston of the California Governor's Office of Emergency Services warned that finding additional sources could be expensive.
"Our big concern is how the fire could affect the infrastructure of this system," Huston told HuffPost. "We have expensive and remote power lines and hydroelectric power stations all in the middle of nowhere."
Protecting said infrastructure was part of the motivation behind California Governor Jerry Brown's declaration of a state of emergency in San Francisco.
"We have to treat that infrastructure like a critical resource, just like the sequoias and Yosemite," said Huston. "So we're taking every possible precaution."
The fire, which has been burning without known cause since August 17, has already destroyed over 160,000 acres, an area roughly the size of Chicago.
Firefighters contained 20 percent of the fire on Monday--tripling progress from just one day prior--but not before it consumed the century-old Tuolumne Family Camp and burned it to the ground. Longtime supporters held a memorial for the popular 15-acre destination in Berkeley on Monday night.