A wildfire threatening Yosemite National Park’s largest grove of giant sequoias has more than doubled in size in a day as firefighters scramble to protect the iconic trees.
More than 500 mature redwoods were threatened in Mariposa Grove in the vast California park, but no serious damage was reported to any named trees, including the 3,000-year-old Grizzly Giant.
The cause of the Washburn fire was under investigation. It had grown to nearly 2.5 square miles (6.7 square kilometers) by Sunday morning.
Beyond the trees, the community of Wawona, which is surrounded by a park and campground, was under threat as people were ordered to leave their homes and campsites on Friday evening.
The blaze proved difficult to contain, with firefighters using “every tactic imaginable” including dropping fire retardant from the air, said Nancy Phillipe, spokeswoman for Yosemite’s fire news.
Firefighters planned to use bulldozers to create lines of fire protecting Wawona, she said. About 600 to 700 people who were staying at the Wawona campsite in tents, cabins and a historic hotel were ordered to leave.
Temperatures were expected to rise in the coming days, but fire crews working in steep terrain weren’t facing intense winds, said Jeffrey Barlow, senior meteorologist with the National Weather Service in Hanford.
Smoke had settled over large swathes of the park, but the fire was not sending up huge plumes seen a day earlier, Mr Barlow said on Sunday.
Given the relatively small size of the blaze and minimal winds, smoke impacts are not expected to extend far beyond the park, he added.
So far in 2022, more than 35,000 wildfires have burned nearly 4.7 million acres, according to the National Interagency Fire Center, well above the average for wildfires and acres burned.
The giant sequoias, native to about 70 groves spread along the western slope of California’s Sierra Nevada mountain range, were once considered impervious to flames but have become increasingly vulnerable as the blazes of forest are fed by an accumulation of undergrowth after a century of fire suppression and exacerbated drought. by climate change have become more intense and destructive.
Ms Phillipe, the park’s spokeswoman, had previously said some of the massive trunks had been wrapped in fireproof foil to protect them, but she corrected herself on Sunday and said it was not the case for this fire.
Lightning-triggered wildfires over the past two years have killed up to a fifth of an estimated 75,000 tall redwoods, which are the largest trees by volume.
There was no obvious natural spark for the fire that broke out next to the park’s Washburn Trail on Thursday, Ms Phillipe said.
Smoke has been reported from visitors walking through the grove which reopened in 2018 after a $40m (£33m) renovation that took three years.
A violent windstorm tore through the grove more than a year ago and toppled 15 giant sequoias, along with countless other trees.
The downed trees, along with a large number of pines killed by bark beetles, provided enough fuel for the flames.
The park has used prescribed burns to clear the brush around the redwoods, which helps protect them if the flames spread further into the grove.