The disastrous wildfires that swept the island of Maui last week suggest new territory for natural disasters, including the prospect of large urban centers threatened by the blazes.
The fires have killed at least 55 people as of Friday morning, and Maui County Mayor Richard Bissen Jr. has compared the devastation to “a war zone where… a bomb went off.”
President Biden has declared a disaster in the state of Hawaii earlier this week, while Gov. Josh Green (D) said Thursday that hundreds of households have been displaced and that the fires are likely the biggest disaster in the history of the state.
Maui County Fire Chief Bradford Ventura also confirmed Thursday that none of the four major fires on the island are fully contained.
While wildfire damage is often associated with forested or remote areas or smaller towns, the Maui fires have also taken a toll on larger population centers.
“People literally running for their lives, barefoot down the street and jumping in the ocean — that’s how fast the fire spread down the slopes and into town,” Daniel Swain, a climate scientist at the University of California, Los Angeles, said during a Wednesday webinar.
“These look like disaster movie scenes, but these are real world events that just took place in Hawaii on the island of Maui,” he added.
Swain, who is also a research fellow at the National Center for Atmospheric Research, described “a catastrophic wildland urban interface firestorm” that spread under unusually dry and windy conditions, particularly on the western side of Maui.
The blaze was able to thrive by “quickly moving into a highly populated area and then becoming essentially an urban conflagration,” he explained. Many residents were unable to flee and telecommunications were severed, meaning that “this is not a case where no news is good news,” according to Swain.
Chris Field, director of the Stanford Woods Institute of the Environment, shared a similar perspective about the Maui fires, expressing his surprise about “how many different ways there are for wildfires to become catastrophic.”
“This fire in Maui wasn’t gigantic and it certainly wasn’t in an area that’s heavily forested,” he told The Hill.
Nonetheless, scientists are increasingly finding “that the combination of dry fuels and high winds can make lots of different kinds of places vulnerable to wildfire,” he explained. This is why the Maui disaster developed “in a place that isn’t a classic wildfire area,” according to Field.
“It doesn’t have big forests, it doesn’t have a long dry season, the kinds of things we associate with wildfires in California,” he said.
Multiple, large fires ended up moving from east to west, primarily on Maui but also on the Big Island of Hawaii, according to Swain. The eastern sides of most Hawaiian islands tend to be much wetter than the western sides, which Swain characterized as “rain-shadowed by the interior of the island.”
These variations in precipitation mean that western slopes often feature brush and shrub lands, while the eastern sides house more of the lush subtropical rainforests, Swain explained.
“One of the important factors in the Maui fire is the abundance of non-native, rapidly growing grasses,” Field agreed, noting that such tall grasses can dry out in just a few weeks.
“And in many tropical and subtropical areas, we’ve seen that the invasion of ecosystems by specially African and Asian grasses has resulted in much higher fire risk,” he added.
University of Hawaiʻi at Mānoa wildfire expert Clay Trauernicht, echoed these sentiments, describing in a statement how “tropical grasses or shrubs from across the world that thrive in fires take over.”
“Non-native grasses like guinea grass and haole koa significantly increase fire potential,” Trauernicht said.
Despite the unique features of the Hawaiian archipelago, many of the factors that made the fires spread the way they did on Maui could repeat themselves in the continental U.S. as well in the right circumstances.
Similar dynamics have already been observed in recent blazes in California, where recent fires in the Mojave Desert occurred in areas that traditionally don’t have enough vegetation for fires to spread out of control, according to Field.
But after a season of heavy rainfall fueled grass growth, the abundance in vegetation allowed “the fire to move from Joshua Tree to Joshua Tree,” Field said.
Exacerbating the effects of these dry fuel ignitions are also heavy winds, which Swain said have played a significant role in the spread of blazes in both Hawaii and California.
Potentially driving the Maui fires, according to Swain, was the combination of unusually high pressure from north and a “fairly strong hurricane a few 100 miles from the south.”
“It is very possible that the presence of a hurricane relatively nearby but not close enough to produce any precipitation helped amplify a downslope windstorm on the Big Island and in Maui,” he added.
This windstorm, Swain continued, could have both contributed to the fire spread and generated drying effects similar to that of a Santa Ana windstorm in Southern California.
These winds also prevented helicopters from performing aerial water drops, which could have helped reduce some of the spread, according to Trauernicht.
Swain warned that there are many more hotspots across the U.S. that could be at risk of wildfires, noting that he would not be shocked “in the coming years to see a wildfire catastrophe unfold in New Jersey, in the Pine Barrens” and in nearby coastal communities.
He offered similar thoughts about the Blue Ridge Mountains in western North Carolina and in parts of the Upper Midwest.
Addressing what role climate change may be playing in fueling this fire, Swain stressed that asking about such a link “just isn’t a well-posed question.”
“Climate change is not the only factor at play,” he said, noting that research does show that it is increasing wildfire risk. “It doesn’t make sense to ask the question of did climate change cause this fire catastrophe? The answer is no. But then nothing else singularly did either.”
These conditions are likely the result of a combination of compounding factors, including climate change, as well as forest management practices that excluded natural fires and Indigenous burning and residual dry fuels, according to Swain.
“We’ve added more fuel to the fire, kiln-dried the fuel with climate change, and then lots of people have moved into the kiln,” he said. “Not a great combination.”
Field also emphasized the role of climate change in the ongoing crisis, and said no lasting solution could ignore that factor.
“It’s important to remember that wildfire has a climate change component behind it almost all the time,” he said. “And the main strategy we should be using in tackling the increasing risk of wildfires is tackling climate change.”