A state of emergency has been declared in California’s Mariposa County after a huge wildfire destroyed at least 10 homes, with more than 6,000 people evacuated.
More houses remain at risk after the blaze near Yosemite National Park erupted to become one of the biggest of the year.
Firefighters were called on Friday afternoon but around 400 are now battling the flames, which covered 19 square miles by Saturday.
Cal Fire has described the ‘explosive fire behaviour’ as ‘challenging’.
Hot weather, low humidity and bone-dry vegetation are making for tough conditions.
Scientists have warned climate change is resulting in increasingly destructive and unpredictable wildfires.
Daniel Patterson, a spokesman for the Sierra National Forest, said: ‘The fire is moving quickly.
‘This fire was throwing embers out in front of itself for up to two miles yesterday. These are exceptional fire conditions.’
An investigation has been launched into the cause of the so-called Oak Fire.
The fast-growing blaze prompted state transport officials to order numerous road closures.
This included a shutdown of Highway 140 between Carstens Road and Allred Road, which blocked one of the main routes into Yosemite National Park.
The Oak Fire flared up as firefighters made progress against an earlier blaze that burned to the edge of a grove of giant sequoias in the southernmost part of Yosemite.
The Washburn Fire was 79% contained on Friday after burning about 7.5 square miles of forest.
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