US Yosemite National Park wildfire grew over 50% overnight, alert issued for visitors

The Washburn Fire raging in Yosemite National Park, one of the most popular national parks in the US, grew more than 50 per cent overnight, spreading to 703 acres in size.

According to the latest data released on Saturday by the InciWeb, an interagency all-risk incident information management system in the US, the fire burning near the lower portion of Mariposa Grove remained 0 per cent contained, reports said.

Hundreds of firefighters are battling from the ground and air to save the historic place, which houses thousand-year-old giant sequoias.

Mariposa Grove was closed since the fire occurred on July 7 and two campgrounds nearby have been evacuated Saturday, but other parts of the park are still open.

Officials from Yosemite warned tourists who are visiting the famous national park located in California this weekend to be prepared for long delays at entrance stations as well as smoky conditions and poor air quality there.

The western US has been ravaged by wildfires in recent years, exacerbated by drought conditions tied to climate change.

In California alone, more than 2.5 million acres were destroyed in nearly 9,000 fires last year,.