Hawaii Wildfires Are Getting More Frequent as Drought Withers Invasive Grass

Wildfires in Hawaii used to be rare and small, kept in check by rainfall. But extreme weather and invasive grasses mean blazes are getting more frequent and more dangerous.

(Bloomberg) — Wildfires in Hawaii used to be rare and small, kept in check by rainfall. But extreme weather and invasive grasses mean blazes are getting more frequent and more dangerous. 

The fires that erupted on Maui this week, destroying the seaside town of Lahaina, are part of a pattern of increasing activity on the islands. Researchers blame drought, hurricane winds and the spread of non-native grasses that, when dry, make excellent fuel.

“We’ve been talking about the need to deal with this fuel problem for a long time now,” said Clay Trauernicht, a wildfire management specialist at the University of Hawaii at Manoa. The Lahaina fire, he said, “is the worst-case scenario many of us have feared.”

The state used to average 5,000 acres (2,023 hectares) burned per year, he said. In the 1990s, however, it jumped to 20,000 or more. The timing coincided with the closure of many farms and ranching operations, as agriculture’s importance to the local economy faded. Grasses imported to the island by humans took over fallow plots and kept spreading.

At the same time, the amount of rain hitting the islands has dropped. From 1920 to 2012, 90% of the state grew drier, according to a 2016 study in the International Journal of Climatology. Some 36% of Maui County is currently in moderate or severe drought, according to the US Drought Monitor. Hawaii’s exposure to the trade winds, which blow east to west, also mean that the eastern parts of each island get far more rain than the west. Lahaina, for example, lies on Maui’s west coast.

Read more: Wildfire Expert on What Fed Deadly Flames in Hawaii: Q&A

Climate change has also supercharged hurricanes and tropical storms. The fires this week happened as Hurricane Dora passed well south of Hawaii, lashing the islands with wind rather than rain. In 2018, hurricanes Hector and Lane fanned wildfires across the islands. 

“It is difficult now in a time when global warming is intensifying the strength of these storms and drought,” Hawaii Governor Josh Green said Thursday. “Climate change is here, and it’s affecting the islands.”

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