Out of control Oak Fire near Yosemite National Park grows into one of the biggest blazes of the year in the western US state, forcing thousands of residents to flee, officials say.

Evidence of global heating could be seen elsewhere in the US, as 85 million Americans in more than a dozen states were under a weekend heat advisory.
Evidence of global heating could be seen elsewhere in the US, as 85 million Americans in more than a dozen states were under a weekend heat advisory. (AP)

A fierce California wildfire has expanded burning several thousand acres and forcing evacuations, as tens of millions of Americans sweltered through scorching heat with already record-setting temperatures due to climb even further.

More than 2,000 firefighters backed by 17 helicopters have been deployed against the Oak Fire, which broke out Friday near Yosemite National Park, the California Department of Forestry and Fire Protection (CAL FIRE) said in a report on Sunday.

But two days after it began the blaze had already consumed more than 14,200 acres and remained zero percent contained, the report said, adding that heat combined with low humidity would "hamper" efforts on Sunday.

"Extreme drought conditions have lead to critical fuel moisture levels," according CAL FIRE's report.

READ MORE: California forest burns as temperatures rocket in western US

'Explosive' fire

Described as "explosive" by officials, the blaze has left ashes, gutted vehicles and twisted remains of properties in its wake, as emergency personnel worked to evacuate residents and protect structures in its path.

It has already destroyed 10 properties and damaged five others, with thousands more threatened.

More than 6,000 people had been evacuated, said Hector Vasquez, a CAL FIRE official.

"It was scary when we left because we were getting ashes on us but we had such a visual of this billowing. It just seemed like it was above our house and coming our way really quickly," one woman who had to be evacuated, Lynda Reynolds-Brown, told local news station KCRA.

California Governor Gavin Newsom on Saturday declared a state of emergency in Mariposa County, citing "conditions of extreme peril to the safety of persons and property."

In recent years, California and other parts of the western United States have been ravaged by huge and fast-moving wildfires, driven by years of drought and a warming climate.

READ MORE: US authorities order evacuation as wildfire spreads in California

Gore blasts 'inaction'

Evidence of global heating could be seen elsewhere in the country, as 85 million Americans in more than a dozen states were under a weekend heat advisory.

The crisis prompted former vice president Al Gore, a tireless climate advocate, to issue stark warnings Sunday about "inaction" by US lawmakers.

Asked whether he believes US President Joe Biden should declare a climate emergency, as Biden has said he soon might, Gore was blunt.

"Mother Nature has already declared it a global emergency," he told ABC News talk show "This Week."

And "it's due to get much, much worse, and quickly," he said on NBC.

But he also suggested that recent crises, including deadly heat waves in Europe, could serve as a wake-up call for members of Congress who have so far refused to embrace efforts to combat climate change.

The worst wildfire season on record in California was in 2020, in terms of total acreage burned, with more than 4 million acres and over 10,000 homes and other structures destroyed. At least 33 lives were lost. Over 10 million acres went up in flames across several Western states.

READ MORE: California firefighters gain against fire threatening Yosemite sequoias

Source: TRTWorld and agencies