SAN FRANCISCO (AFP) – Nearly four thousand firefighters battled a fierce blaze on the edge of world famous Yosemite National Park on Tuesday amid fears it could contaminate San Francisco’s drinking water supply.
“I see another intense fire day,” said Lee Bentley of the U.S. Forest Service, as crews raced to douse the dangerous flames.
The so-called Rim Fire, the 13th largest in state history, has shut the road into one of the country’s top tourist destinations.
Ten days after it broke out it is only 20 percent contained, the California Department of Forestry and Fire Protection said.
The powerful blaze had charred 179,481 acres, spokesman Daniel Berlant added in a Twitter update Tuesday.
He said more than 3,700 firefighters were battling the blaze, which began 10 days ago. What sparked it remains unclear.
Although ash from the inferno has reached the reservoir that supplies San Francisco’s drinking water, crews said they were confident public health can be protected, local news reports said.
The Hetch Hetchy Reservoir is the main source of fresh water for 2.6 million people living in the San Francisco Bay Area, located some 200 miles to the west.
“Water quality is not currently impacted by the Rim Fire,” the San Francisco Public Utilities Commission said in the latest update on its website.
The statement added: “We are monitoring water quality every minute of each day to ensure its quality and safety.”
The fire is also threatening the iconic giant sequoia trees in Yosemite.
“They are definitely in danger, but we’re doing everything we can,” Bentley told CNN when asked about the trees.
“We’ve got a pretty good chance of keeping it away, but it’s going to take a heck of a lot of work and a lot of air power,” Bentley said.
Schools in several nearby areas were expected to stay closed Tuesday.
Meanwhile, the park said on its website that “most of Yosemite National Park is not affected by the fire and is relatively smoke-free. The northern part of the park… has some smoke. Conditions may change if winds shift.”
Highway 120, one of the main routes into Yosemite from the west, was closed due to the fire.
Governor Jerry Brown has declared a state of emergency for San Francisco due to the threat to its water and even power supplies.
Two hydroelectric power plants have not been in use since August 19 due to the fire, the San Francisco Public Utilities Commission said on its website.
The state’s firefighting efforts got a boost when California received federal assistance over the weekend to help mobilize the necessary resources.
President Barack Obama spoke to California’s governor on Sunday and “expressed his gratitude for the brave men and women working tirelessly to combat this devastating fire.”
“The President reiterated his commitment to providing needed federal resources to support the ongoing state and local response,” the White House added, in an account of the call.