Hawaii video shows natural fireline shape, experts say

"Perfect Circle Burning in The Maui Fires, DOES THIS LOOKS NATURAL TO YOU?!?" says Matt Wallace, a far-right social media personality who has previously promoted misinformation, in an August 13, 2023 post on Twitter, which is being rebranded as "X."

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Screenshot taken August 17, 2023 of a post on Twitter, which is being rebranded as "X"

Several similar posts spread on Facebook, Instagram and TikTok.

"Anyone telling you that this was the result of something natural is either being paid to tell you that or they’re disconnected from reality," says an August 15 post on Instagram.

The claims come after blazes decimated parts of the island of Maui in early August, killing more than 100 people in the deadliest US wildfire in more than a century. The tragedy inspired conspiracy theories about the fires' origin, with some social media users falsely claiming they were set intentionally using lasers to create more climate-friendly cities.

But experts say the shape of the fireline in the aerial video shared online is common.

"This is completely natural and expected under the environmental conditions observed in the short video, as limited as that is," Christopher Dunn, an assistant professor in Oregon State University's College of Forestry, told AFP in an August 15 email.

Arnaud Trouve, professor of fire protection engineering at the University of Maryland, agreed, saying there is "nothing unusual about the observed fireline shape."

Wildfires typically spread in an ellipse if certain conditions are met, Trouve said in an August 15 email. Among them: flat terrain, uniform vegetation and consistent wind conditions.

"The reality is quite the opposite of what this tweet suggests," said Michael Gollner, an associate professor of mechanical engineering at the University of California-Berkeley who leads a fire research lab, in an August 15 email.

"The reason we don't always see this ellipse is that fuels and topography aren't always uniform. The incredibly high winds and uniform grass in Maui make ideal conditions for a textbook wildfire spread case."

The exact cause of the Maui fires is still under investigation. But Susan Buchanan, director of public affairs for the National Weather Service, previously told AFP the agency alerted local officials up to a week in advance "about dangerous fire weather conditions on the Hawaiian Islands," issuing official warnings in the days before the inferno began (archived here).

"A mix of dry vegetation, strong winds, dry subsiding air and low relative humidity helped to spread the deadly fires once they were ignited," Buchanan said.

The Washington Post and other US media have reported that fallen power lines from the state's main utility may have triggered the first blazes. A class-action lawsuit has been filed against Hawaiian Electric.

AFP has debunked misinformation about past wildfires here and here.