Approximately 5,500 people were ordered to evacuate areas north of Honolulu on Friday after torrential rains pushed a 120-year-old dam on Oahu dangerously close to overflowing, triggering what Hawaii’s governor called the state’s worst flooding in more than two decades. The Wahiawa Dam, a 660-foot-long earthen structure built in 1906 and owned by the Dole Food Company, strained under a deluge that dumped up to 16 inches of rain on the island’s highest peak, according to NPR.
Evacuation orders were issued for residents of Waialua and Haleiwa due to potential life-threatening flooding from the dam, which can hold up to 9,200 acre-feet of water — roughly the equivalent of 4,600 Olympic-sized swimming pools, as NBC News reported. Molly Pierce, spokesperson for the Oahu Department of Emergency Management, said a little over 4,000 people live directly within the dam evacuation area, though the number in the broader flood-impacted North Shore region is closer to 10,000.
Parts of Oahu received 8 to 12 inches of rain overnight, while Kaala, the island’s highest peak, was drenched with nearly 16 inches in a single day, according to the National Weather Service. The sudden onslaught overwhelmed drainage systems and turned roads into rivers, stranding residents across the island.
Governor Josh Green described the flooding as the state’s most serious since 2004 floods in Manoa that inundated homes and a University of Hawaii library. In a CNN interview, Green said crews rescued 236 people from flooding conditions, with about 10 of those individuals taken to a hospital suffering from hypothermia. No deaths were reported as a result of the flooding, the governor confirmed.
The scope of the destruction was staggering. Honolulu Mayor Rick Blangiardi said dozens if not hundreds of homes were damaged on Friday, though officials had not yet been able to fully assess the extent. Green estimated the storm could cost more than $1 billion in damage across public and private sectors statewide, including damage to airports, schools, roads, homes, and a Maui hospital in Kula. He also closed state offices and departments on Friday, with the exception of emergency management, sending employees home.
In one dramatic rescue, the National Guard and Honolulu Fire Department airlifted 72 children and adults from a spring break youth camp at Our Lady of Kea’au retreat on Oahu’s west coast, according to CBS News. On Maui, crews were searching for a 71-year-old woman who reportedly fell into Iao Stream and was swept away.
The Wahiawa Dam has a troubled history that long predates this week’s crisis. Originally constructed to increase sugar production for the Waialua Agricultural Company — which later became a subsidiary of Dole Food Company — the dam was rebuilt after collapsing in 1921. A 2020 inspection by Hawaii’s Department of Land and Natural Resources found it in poor condition, and the state has sent Dole four notices of deficiency about the dam since 2009, fining the company $20,000 for failing to address safety issues on time.
Hawaii passed legislation in 2023 authorizing the acquisition of the dam from Dole, providing $5 million to purchase the spillway and $21 million to repair and expand it to comply with dam safety standards. However, the transfer had not been completed before the storm struck.
Dole Food Company Hawaii maintained that the dam remained stable and structurally sound throughout the emergency. The spillway was designed to operate at 80 feet and was functioning as intended, the company said. The dam crest sits at 88 feet, and a portable AquaDam was deployed to increase capacity to approximately 90 feet, according to Hawaii News Now.
Water levels at the dam began to fall later Friday night, and the flash flood warning and evacuation notice were lifted at about 3 p.m. local time Saturday. Still, the close call renewed scrutiny of Hawaii’s aging infrastructure. The state regulates 132 dams, most built as part of irrigation systems for the sugar cane industry, according to a 2019 infrastructure report by the American Society of Civil Engineers, as ABC News noted.
The risks of neglecting those structures are well documented. In 2006, seven people were killed when the Ka Loko dam on the island of Kauai collapsed and water rushed downhill. That tragedy helped spur tighter dam safety regulations, but critics say enforcement and funding have lagged behind the scale of the problem.
As residents returned to waterlogged homes over the weekend, the full extent of the damage remained unclear. Officials warned that assessments would take days, and the billion-dollar cost estimate could grow as inspectors reach areas that were inaccessible during the height of the flooding.
