As Hawaii begins to clean up and assess the damage from Hurricane Lane, which dumped more than 40 inches of rain on the islands to become one of the wettest storms in U.S. history, the state is wrestling with what may be its new, wetter reality. The deluge was Hawaii’s second devastating rain event this year as the state absorbed 49 inches from an extreme downpour in early May.
Climate scientists have predicted that climate change would make hurricanes wetter—because a warmer atmosphere holds more moisture and warmer oceans provide more energy for storms—and the events of the past year have brought significant evidence to support that. Last August, Hurricane Harvey inundated the Houston area with more than 60 inches of rain, the most rain ever recorded from a tropical storm system in the U.S. Studies have already shown that Harvey’s rainfall was more than triple what it would have been without global warming. Another study published last August suggests these storms “will become stronger, larger, and unexpectedly more destructive under global warming.”
Penn State scientist Michael Mann calls rising carbon dioxide levels in the atmosphere “steroids for the storms.”
In what could be worse news for Hawaii, a recent study showed warming waters in the Pacific could double the tropical storm activity around that area by 2100 if global warming continues toward 2 degrees C over pre-industrial times. The state has been directly hit by only three major hurricanes since 1871, although one of them—Hiki, which dumped 52 inches of rain on the state in 1950—is the second wettest in U.S. history after Harvey.
The state’s climatologist, Pao-Shin Chu, despite describing the scenario around Hawaii as holding the potential for more rain damage, said in an email, “With more moisture in the air, storms may be wetter but I think we should be cautious about attributing the past two events in Hawaii to climate change unless we see a continued trend in severe storms impacting Hawaii (or elsewhere).”
With Lane now passed, the state begins tallying the costs. The extreme rainfall means that damage will be more from flooding, mudflows and beach erosion than from the high winds usually associated with hurricanes or tropical storms. Typically homeowners’ insurance that covers hurricane damage will pay for wind damage but excludes flood damage. Flood insurance must be purchased separately. This means that many Hawaiians may find their property damage is uninsured.
Damage estimates are expected to be in the millions, if not billions, of dollars. “All told, hundreds of homes have been destroyed or damaged, and over a thousand were forced to take temporary shelter from destructive weather, and the continued threat of flood and fire. The state’s economy has also been harmed. Countless businesses have been compromised by physical damage and lost revenue, and the whole event has had significant negative impacts to Hawaii’s visitor industry,” Hawaii’s congressional delegation wrote in a letter to Federal Emergency Management Agency administrator Brock Long on Monday.
Although Lane, originally forecast as a category 5 hurricane, was downgraded to a tropical storm, its intense rainfall brought significant flooding and landslides.
The town of Mountain View on the Big Island recorded 51.53 inches of rain over five days. The Big Island was the hardest hit, but the tourist hub of Maui also recorded landslides and damaged infrastructure.