© The Guardian
Extraordinary footage shows a fire tornado ripping through Los Angeles County in Gorman on Wednesday.

Firefighters were dispatched to a wildfire, dubbed the Sam Fire, at 4:07 p.m.

Arriving on the scene, Los Angeles County Fire Department said an estimated four acres was ablaze, which they later categorized as a second-alarm brush fire.

Video published by local news site KTLA shows large quantities of air being sucked into a vortex-like fire tornado.

Filmed by helicopter, a man can be heard describing the fire tornado as "the biggest one I've ever seen."

Fire tornadoes, also known as fire whirls, can occur when intense, rising heat mixes with powerful winds. This results in the fire spinning upwards, where it drags in more gas and debris as fuel.

Fire whirls are defined by the United States Department of Agriculture Fire Service as "spinning vortex column of ascending hot air and gases rising from a fire and carrying aloft smoke, debris, and flame."

The department says: "Fire whirls range in size from less than one foot to more than 500 feet in diameter. Large fire whirls have the intensity of a small tornado."

A photo of the inferno was tweeted by the Los Angeles County Fire Department's air operations section, who said: "Short range spotting and fire whirls on the #SamFire tell the story of dry, receptive fuels and erratic winds from intense surface heating."

When firefighters first arrived on the scene they estimated the fire's size as four acres, though this grew to 150 acres by the evening, at which point the blaze was contained.

A tweet from the fire department at 5:16 p.m. said 200 emergency responders were battling the blaze, and "making good progress."

By 11 p.m. local time, 60 percent of the inferno had been contained.

No buildings were immediately threatened by the fire, which took place on rough, hilly terrain. However, as a precaution, California Highway Patrol did shut down Highway 138 for a time.

The County of Los Angeles Fire Department has been contacted for comment.

California has been hit by a number of wildfires this summer, leaving thousands of acres scorched.

In July, the Washburne fire engulfed 3,500 acres of the Yosemite National Park before being contained.

Two months earlier, at least 20 homes were burned by a fire which swept through the coastal Laguna Niguel area of southern California, with the blaze reaching 195 acres.

In 2021, a video of California firefighter Meg Hayes starting controlled fires went viral on TikTok, earning more than 1.4 million views after being posted on June 23.

Controlled fires are a tactic that can be used to fight wildfires, depriving them of the fuel they need to spread to certain areas.