Explosive wildfire near Yosemite grows, forcing thousands of evacuations: "It's absolutely terrifying"

A fierce California wildfire expanded Monday, burning several thousand acres and forcing evacuations as tens of millions of Americans sweltered through scorching heat over the weekend. More than 2,000 firefighters backed by 17 helicopters have been deployed against the Oak Fire, which broke out Friday near Yosemite National Park, according to the California Department of Forestry and Fire Protection, or Cal Fire.

But three days after it began, the blaze has already consumed more than 16,700 acres and was 10% contained as of early Monday morning, the agency said.

"Extreme drought conditions have led to critical fuel moisture levels," according to Cal Fire.