Residents on Oahu are facing the worst flooding the state has seen in more than 20 years as winter storms forced thousands from their homes to seek higher ground.
The North Shore, famed for its surf, has been hardest hit, and forecasters expect additional rain in the days ahead. Torrents of muddy water swept across the island Thursday and Friday, carrying away cars and homes, washing out roads and prompting the evacuation of at least 5,500 people north of Honolulu.
“This is going to have a very serious consequence for us as a state,” Governor Josh Green said Friday, adding that the flooding is the worst since 2004. He estimated total damage to private and public property could exceed $1 billion (€860 million). Honolulu Mayor Rick Blangiardi called the destruction “catastrophic.”
Meteorologists say Hawaii regularly sees wet winter weather from so-called “Kona lows,” but experts argue these systems have been intensified by human-driven changes that increase storm frequency and strength. National Weather Service crews at Kaala, Oahu’s highest peak, measured 16 inches (40 cm) of rain overnight Thursday, while other areas recorded 8 to 12 inches. The NWS issued flood watches statewide and flash flood warnings for the North Shore. Mayor Blangiardi warned another 6 to 8 inches of rain could fall over the next two to three days.
Officials report no fatalities so far but said about 10 people were hospitalized with hypothermia. Rescue teams have pulled more than 230 residents to safety, including about 70 children and adults airlifted from a Catholic youth camp by the National Guard and the Honolulu Fire Department. Rescues have been complicated by people flying drones over affected areas to capture images and video.
A major ongoing danger is the Wahiawa Dam, which authorities say is “at risk of imminent failure” and have labeled “high-hazard potential,” warning that a breach “will result in probable loss of life.” The earthen dam, built by Dole in 1906 and rebuilt after a 1921 collapse, is near capacity; as of Friday its reservoir reached about 25.6 meters, roughly 1.8 meters below overflow after rising more than 1.5 meters overnight.
State officials have pressed Dole to address the dam’s safety since 2009. Five years ago the company was fined $20,000 for not resolving concerns. Dole has offered to donate the dam, reservoir and ditch system to the state if Hawaii agrees to repair the spillway to meet safety standards. Legislation enabling the state’s acquisition passed in 2023, and a state board is scheduled to vote on the transfer next week. Dole said Friday that “the dam continues to operate as designed with no indications of damage.”
Hawaii oversees 132 dams, many originally built for sugar cane irrigation, the American Society of Civil Engineers notes.
Oahu’s Emergency Management Agency ordered about 4,000 residents downstream of Wahiawa Dam to “LEAVE the downstream area NOW!” On Saturday, officials again urged people to evacuate parts of the island and use emergency shelters set up by authorities and local groups as flash flooding was either occurring or imminent. Residents were encouraged to carpool where possible as roads were becoming increasingly impassable.
Edited by: Kieran Burke