Wildfires continue to spread in Yosemite National Park in the US state of California. More than 4,800 hectares of the nature reserve are now burning, making the oak fire the biggest fire of the season.

The fire service reported that more than 6,000 people were evacuated from the area, several roads were closed, and the fire threatens about 2,000 buildings. So far, no deaths or injuries have been reported. The governor of California declared a state of emergency in the region.

The fire broke out on Friday afternoon and has since increased in size sixfold. High temperatures, dryness and low humidity contribute to the strong expansion of fire.

More than 400 firefighters were deployed to fight the fire. They use helicopters, firefighting planes, and bulldozers, among other things. So far, the fire has not been brought under control.

The southwestern United States has been battling wildfires for some time now. Almost two weeks ago, a major fire broke out in Yosemite Park itself. The fire then approached the edge of Mariposa Grove, which has more than 500 redwoods. Many of these giant trees are thousands of years old.

The fire brigade eventually managed to save the trees.