Yosemite closure extended into the weekend, Hetch Hetchy area shut down

The closure of Yosemite Valley has been extended until Sunday because of ongoing smoky conditions. The closure of Yosemite Valley has been extended until Sunday because of ongoing smoky conditions. Image 1 of / 1 Caption Close Yosemite closure extended into the weekend, Hetch Hetchy area shut down 1 / 1 Back to Gallery

Yosemite National Park officials on Tuesday extended the shutdown of much of the park until Sunday because of ongoing wildfire concerns while expanding the closure to include the Hetch Hetchy area.

Popular Yosemite Valley as well as the Wawona area, Mariposa Grove and Merced Grove have been closed since July 25 due to unhealthy smoke and firefighting traffic from the nearby Ferguson Fire. Despite plans to reopen the affected areas Friday, officials said conditions have not improved enough to lift the closure. In fact, they’ve worsened in some spots.

The same smoky haze that has polluted Yosemite Valley has moved into the Hetch Hetchy area, officials said, prompting the shutdown of this section of the park Tuesday. A San Francisco Public Utilities Commission spokesman said officials are monitoring the water quality but had no concerns at this time. Hetch Hetchy reservoir provides drinking water for San Francisco and other cities served by the SFPUC.

The only major corridor that remained open was Highway 120 to Tuolumne Meadows.

The Ferguson Fire, which ignited July 13 in the nearby Sierra National Forest, has charred more than 57,846 acres and was just 33 percent contained as of Tuesday afternoon. The blaze has not moved into the park.

Kurtis Alexander is a San Francisco Chronicle staff writer. Email: kalexander@sfchronicle.com Twitter: @kurtisalexander