The wildfire burning at Yosemite National Park is now the sixth biggest in California history but it is now 30 percent contained, officials said Thursday.
The blaze now covers more than 192,000 acres, or 300 square miles, according to the California Department of Forestry and Fire Protection (Cal Fire).
The level of containment, however, has increased from just 23 percent on Wednesday.
Crews battling the blaze plan to use a technique called backfires on a large scale. This involves setting fires inside containment lines to char vegetation and deny fuel to advancing flames, the Los Angeles Times reported.
The fire started August 17, and recently forced the closure of a second main road into the major US tourist attraction ahead of the Labor Day weekend.
Cal Fire spokesman Daniel Berlant told the Times that full containment of the fire is expected by September 10, as crews get help from cooler temperatures, higher humidity and lighter winds.
On Labor Day a surge of visitors is typically expected at California’s Yosemite National Park, which draws millions of tourists every year.
As well as clouding the tourist spot, the so-called Rim Fire is also threatening to contaminate San Francisco’s water supply, as it drops a rain of ash onto a key reservoir feeding the West Coast city.
Last week officials closed Highway 120, the main road used by visitors from San Fransisco into the west of the park. There are three other main roads in.
From noon (1900 GMT) Wednesday authorities closed a key section of the Tioga Road, which runs horizontally across the park, effectively blocking access from the east into Yosemite Valley, the spectacular area at its heart.
The road will likely remain closed through the Labor Day weekend to allow crews to carry out fire suppression activities in the area, said park Superintendent Don Neubacher.
The blaze has forced the closure of multiple campgrounds and other facilities in the area, and has also threatened a number of groves of giant sequoia trees, some of the world’s biggest and oldest living organisms.
But it remains more than 15 miles away from the majestic Yosemite Valley, visited by millions of tourists every year to see natural wonders including the Half Dome and El Capitan rock formations.
Ash from the inferno has however reached the Hetch Hetchy Reservoir, the main source of fresh water for 2.6 million people living in the San Francisco Bay Area, some 200 miles (320 kilometers) to the west.
No injuries or deaths have been reported due to the blaze, but it has destroyed at least 111 structures — 31 homes as well as buildings on campgrounds that were hastily evacuated last week when the fire erupted.
Slow but steady fight against Yosemite blaze
