What is a 'fire whirl,' the rare weather phenomenon spotted in a California wildfire

They may sound like something from science fiction, but "fire whirls" are in fact real.

And the flaming vortexes have been spotted in recent days by firefighters battling a blaze along the California-Nevada border, federal authorities say.

"In some locations, firefighters on the north side of the fire observed fire whirls also known as whirlwinds," the Mojave National Preserve said in a Facebook post on Monday.

"While these can be fascinating to observe they are a very dangerous natural phenomena that can occur during wildfires."

Climate change is making the U.S. hotter and drier, increasing the risk of wildfires and in some cases the intensity of blazes.

When wildfires do ignite, they can create their own weather patterns, including fire whirls.

That's when a wildfire plume combines with rotating air to form a "spinning column of fire" akin to a small tornado. As fire whirls stretch higher, they become skinnier and spin faster.

Fire whirls are related to other extreme weather events, such as dust devils, water spouts and fire tornadoes, experts say.

"Fire tornadoes are more of that, the larger version of a fire whirl, and they are really the size and scale of a regular tornado," Jason Forthofer, a firefighter and mechanical engineer at the U.S. Forest Service's Missoula Fire Sciences Lab in Montana, told Montana Public Radio in 2021.

According to the U.S. Forest Service, fire whirls can range in size from less than one meter to three kilometers wide — less than two miles — and vary in speed.

They can present a "considerable safety hazard" to firefighters, given their intensity and unpredictability, the service added.

Forthofer said at the time that it was unclear whether a spike in reports of fire whirls and fire tornadoes could be attributed to more people recording the phenomena or whether the rare weather events were occurring more frequently.

Fire whirls aren't only destructive; they can also be deadly. Following an earthquake in Tokyo in 1923, fire whirls torched parts of three neighborhoods and killed nearly 40,000 people, according to the Association for Asian Studies.

In the U.S., fire whirls have injured firefighters and forced others to deploy emergency shelters, the U.S. Forest Service said.

As of midday Wednesday, the York Fire along the California-Nevada border was more than 80,000 acres in size and was 30% contained. Fire activity had slowed due to rain, officials said.

Authorities in the area warned that fire whirls could endanger the firefighters combating the blaze, since fire whirls are unpredictable and can change direction quickly. They also have the potential to fling embers over vast distances and spark new fires.

Firefighting crews confronting fire whirls face "significant risks, and safety protocols along with strategies must carefully be planned and executed to minimize potential harm," authorities said.