Hawaii has experienced widespread severe flooding, identified as the most significant event since 2004. The conditions prompted evacuations across Oahu and parts of Maui, raised concerns about the Wahiawa Dam's stability, and resulted in an estimated $1 billion in damages. Emergency services conducted numerous rescues, and the Hawaii National Guard was activated in response to the situation.
Overview of Flooding
Heavy rainfall inundated streets and agricultural areas across the Hawaiian islands, particularly Oahu. The flooding has been described by officials as the most severe in over two decades. Following a prior winter storm that saturated the ground, subsequent deluges led to widespread inundation.
Evacuations and Rescues
Officials issued evacuation orders for residents in the Waialua area of Oahu due to potential road failures, impacting approximately 5,500 people north of Honolulu. Maui County also issued an evacuation advisory for some Lahaina neighborhoods as retention basins approached capacity.
As of Sunday afternoon, no fatalities were reported. Over 200 individuals were rescued from floodwaters. Ten people were hospitalized for hypothermia, and 72 adults and children were airlifted from a youth camp on Oahu as a precautionary measure. One shelter at Waialua High and Intermediate School was evacuated due to flooding, necessitating the transfer of approximately 185 people and 50 pets to another center.
Over 200 individuals were rescued from floodwaters, with no fatalities reported as of Sunday afternoon.
Wahiawa Dam Monitoring
The 120-year-old Wahiawa Dam, located approximately 17 miles (28 km) northwest of Honolulu, was declared to be at "risk of imminent failure" by officials. The Hawaii Department of Land and Natural Resources classified the 85-foot earthen dam as a "high hazard potential dam," indicating that its failure could lead to loss of human life.
The dam, built in 1906 and reconstructed in 1921 for sugar production, was later acquired by the Dole Food Company. Dole had received multiple notices regarding dam deficiencies since 2009 and was fined $20,000 in April 2021 for maintenance failures. Dole representatives stated at the time that the dam was operating as designed. The state of Hawaii passed legislation in 2023 to acquire the dam, with the transfer process ongoing.
Water levels at the dam increased from 24 to 25.6 meters, reaching 1.8 meters below its full capacity, with water flowing over its spillway. While initial reports indicated the threat diminished as water levels receded, overnight rain caused levels to rise again.
By Saturday morning, officials stated that broader hazardous conditions across the island, including residential flooding in Honolulu, were a greater immediate concern than the dam's stability. Authorities cautioned that saturated conditions meant minimal additional rainfall could rapidly restore flood levels.
Scope of Damage and Response
Governor Josh Green estimated the storm's cost could exceed $1 billion, affecting infrastructure such as airports, schools, roads, homes, and a hospital. Assessments indicated damage to dozens, potentially hundreds, of homes.
Governor Josh Green estimated the storm's cost could exceed $1 billion, impacting infrastructure and potentially hundreds of homes.
Floodwaters displaced homes and vehicles, submerged agricultural areas, and entered grocery stores, depositing substantial mud. In communities like Waialua and Hale'iwa, mud and debris accumulated in yards.
Governor Green activated the Hawaii National Guard, and the military reserves and Coast Guard were also involved in emergency response and search and rescue operations. Honolulu Mayor Rick Blangiardi stated that the full extent of the damage was still being assessed. The White House affirmed assurances of federal support for the state. In Maui, crews redirected and pumped water to maintain safe levels in retention basins. Road clearing operations were underway in affected areas.
Weather Context and Outlook
The heavy rainfall was attributed to "Kona lows," which are winter storm systems characterized by southerly or south-westerly winds carrying moisture-laden air. These systems are known to cause torrential rains, hailstorms, thunder, and flooding in the Hawaiian islands.
Parts of Oahu received 8 to 12 inches (20 to 30 cm) of rain in a short duration on already saturated ground. Kaala, Oahu's highest peak, recorded nearly 400mm in one day, adding to 670mm received between March 10 and 16. Experts suggest an increase in the intensity and frequency of heavy rains in Hawaii is associated with human-caused global warming.
By Sunday afternoon, the most severe storm activity appeared to conclude, with weather patterns shifting from widespread showers to scattered rain across Oahu, Maui County, and Hawaii Island. Projections indicated less than 5 inches (13 cm) of rain for Hawaii Island and 1 to 2 inches for other regions. Localized flooding remains possible, with drier and more typical March weather anticipated by Wednesday.