Campers and residents near the blaze were evacuated over the weekend, while the rest of the sprawling park remained open, though heavy smoke obscured scenic vistas and created unhealthy air quality.
“Today it’s actually the smokiest that we’ve seen,” Nancy Phillipe, a Yosemite fire information spokesperson, said Sunday. “Up until this morning, the park has not been in that unhealthy category, but that is where we are now.”
More than 500 mature sequoias were threatened in the Mariposa Grove, but as of Saturday afternoon there were no reports of severe damage to any named trees, including the 3,000-year-old Grizzly Giant.
Mariposa Grove and Yosemite Valley have been protected since President Abraham Lincoln signed legislation in 1864.
“Fortunately, the Mariposa Grove has a long history of prescribed burning and studies have shown that these efforts reduce the impacts of high-severity unwanted fire,” a National Park Service statement said.
The cause of the fire was under investigation.
Beyond the trees, the small community of Wawona, which is surrounded by park and a campground, was under threat, with people ordered to leave their homes and campsites on Friday night.
Phillipe said the park posted a video of a temporary sprinkler system installed to protect the trees. She said she’s confident that the sprinkler system combined with previous prescribed burns is the best protection for the trees. “If we were to add the additional foil protection, that would actually create a baked potato effect on the tree, and so we're not doing that,” she said.
An estimated 1,600 people were evacuated, including a hotel, a campground and permanent residents. The Red Cross has set up a shelter in Mariposa, but Phillipe said most people who evacuated ended up not needing to go there.
“Folks coming into the park … just be aware that the air quality today is in the unhealthy range,” she said. “Our priorities remain: firefighters, public safety, the community of Wawona and the giant sequoias in the Mariposa Grove.”