Heavy rainfall associated with Kona-low storm systems has resulted in severe flooding across Hawaii, particularly impacting Oahu, Maui, and the Big Island. The extreme weather prompted evacuation orders for thousands of residents and raised significant concerns about the 120-year-old Wahiawa Dam on Oahu. The storms caused an estimated over $1 billion in damages to infrastructure and property, with rescue operations actively underway. No fatalities have been reported.
Overview of Flooding and Impacts
Hawaii has experienced its most severe flooding in over two decades, affecting multiple islands over a two-week period. Widespread heavy rainfall, falling on ground already saturated from a previous storm, led to extensive muddy floodwaters.
Oahu's North Shore and Southern Oahu
On Oahu's North Shore, including areas like Haleiwa and Waialua, streets were inundated, homes were displaced from their foundations or swept away, and vehicles were submerged. Sinkholes, landslides, and downed trees were also reported.
A separate, highly localized flash flood on Monday delivered 2 to 4 inches (5 to 10 centimeters) of rain per hour to southern Oahu, including the Manoa Valley, resulting in reddish-brown torrents that pushed parked cars and inundated neighborhoods.
Maui County and the Big Island
Maui County faced flood advisories and warnings, with areas like Iao Valley, Kihei, Lahaina, and Molokai impacted by rising waters, damaged bridges, roads, and affected riverbeds.
The Big Island also experienced flood advisories and warnings, with heavy rain in southeastern regions. Summits above 12,000 feet were under a winter storm watch, predicting up to 10 inches of snow and high winds.
Wahiawa Dam Concerns and Status
A primary concern during the flooding centered on the 120-year-old Wahiawa Dam on Oahu, located north of Honolulu. The earthen dam, constructed in 1906 and owned by Dole Food Company, impounds irrigation water for Lake Wilson.
Imminent Failure Risk and Monitoring
Officials issued warnings of an "imminent failure risk" for the dam, prompting immediate evacuation orders for downstream residents. A 2020 inspection had categorized the dam's condition as "poor," and state dam safety officials had monitored structural deficiencies for over a decade. They noted an undersized spillway that might not adequately handle a probable flood, potentially leading to overtopping and failure.
The dam is classified as having "high hazard potential," meaning a failure would likely result in loss of human life.
During the peak of the storm, water was observed flowing over the dam's spillway/crest, and its level rose from 79 feet to 84 feet, reaching within 6 feet of its maximum capacity. A portable AquaDam barrier was deployed to temporarily increase its height.
Dole Food Company stated that it was cooperating with authorities, continuously monitoring the reservoirs, and that the dam was functioning as intended without indications of damage. Concerns about the dam's failure largely subsided as water levels receded by late Friday, though monitoring has continued, with officials remaining vigilant for potential changes with additional rainfall.
History of Deficiencies and State Action
The Wahiawa Dam has a history of safety deficiencies, with the state issuing four notices of deficiency to Dole since 2009. The company was fined $20,000 in 2019 for failing to address safety issues. Legislation passed in 2023 authorized the state's acquisition of the dam, reservoir, and ditch system, allocating $5 million for purchase and $21 million for repairs, though the transfer remains incomplete.
Hawaii regulates 132 dams, many originally built for the sugar cane industry. A 2006 collapse of the Ka Loko dam on Kauai resulted in seven fatalities.
Evacuations and Rescues
Mass evacuation orders were issued for over 4,000 residents initially, later encompassing approximately 5,500 people in towns north of Honolulu, including Haleiwa and Waialua. Sirens were activated, and "Evacuate Now" orders were issued for specific zones downstream of the Wahiawa Dam. These evacuation orders were later lifted.
Rescue Operations
More than 230 individuals were rescued from floodwaters, some from rooftops.
Rescue efforts involved firefighters, lifeguards on jet skis, Honolulu police, and Ocean Safety crews. The Hawaii National Guard deployed High Water Vehicle Teams, and the U.S. Coast Guard launched boat, cutter, and aircraft crews for potential search and rescue. Active duty Army troops were on standby. The National Guard and Honolulu Fire Department airlifted 72 children and adults from a spring break youth camp on Oahu's west coast.
No fatalities or missing persons have been reported in connection with the floods. Approximately 10 individuals were transported to a hospital for hypothermia. Rescue efforts were reportedly hampered by personal drones flown by civilians.
Evacuation Centers
Multiple evacuation centers were opened across Oahu, Maui, and Molokai. On Oahu, centers included Wahiawa District Park, Leilehua High School, Mililani District Park, Kahuku High School, and Nanakuli High School. The shelter at Waialua High and Intermediate School was evacuated and occupants redirected due to dam failure risk.
Infrastructure Damage and Economic Impact
The storm systems caused significant damage across the state, with Governor Josh Green estimating the financial impact could exceed $1 billion. This estimate covers damage to infrastructure such as airports, schools, roads, bridges, private residences, and a Maui hospital.
School Closures and Power Outages
The Hawaii State Department of Education reported 500 work orders related to storm damage at schools, with 13 public schools across Oahu, Molokai, and Hawaii island closed for assessment and repairs.
Power outages affected nearly 6,800 customers statewide initially, with approximately 4,200 in Oahu’s North Shore evacuation zones experiencing proactive shutoffs. Hawaiian Electric crews worked to restore power, with over 2,000 customers on Oahu's North Shore and 100 in Maui County remaining without power at times.
Agricultural and Property Damage
Agricultural damage across the state exceeded $9.4 million, with Oahu farms reporting over $2.7 million in crop losses. Residents described homes covered in thick volcanic mud and silt, causing significant cleanup challenges.
Official Response and Aid
Governor Josh Green activated the Hawaii National Guard, closed Hawaii state offices (with the exception of emergency management) on Friday, and confirmed receipt of assurances for federal support from the White House. He later submitted a major disaster declaration request to the administration.
Honolulu Mayor Rick Blangiardi urged the public not to underestimate the storm's unpredictability and confirmed ongoing emergency and rescue operations. The city’s Emergency Operations Center was activated for non-emergency inquiries. The Mayor characterized a Monday flash flood event as a "classic rain bomb" with no prior warning.
A boil water notice remained in effect for North Shore areas from Mokuleia to Turtle Bay. The Oahu Emergency Management Agency confirmed that volunteers, public workers, and a contract company were engaged in collecting and removing debris.
Weather Conditions and Climate Context
The severe weather was attributed to "Kona lows," which are winter storm systems characterized by southerly or southwesterly winds carrying moisture-laden air.
Rainfall Totals and Forecast
Parts of Oahu received between 8 to 12 inches (20 to 30 cm) of rain overnight during the peak of the storms. Kaala, Oahu's highest peak, recorded nearly 16 inches (40 cm) within a day, and 26.6 inches (67.6 cm) between March 10 and 16. An additional 6 to 8 inches (15 to 20 cm) of rain was forecast for Oahu.
National Weather Service meteorologists expressed surprise at the intensity of some localized downpours, noting that models did not accurately predict the volume of moisture. Forecasters anticipated the heaviest rain to gradually subside, with conditions expected to improve from west to east starting Monday and typical March weather anticipated by Wednesday.
Climate Change Connection
Experts indicate that the intensity and frequency of heavy rains in Hawaii have increased, a trend that they associate with human-caused global warming.
Recovery Efforts and Ongoing Situation
Cleanup efforts are underway, with volunteers from Oahu and other islands assisting in clearing debris and mud from affected properties. Organizations such as the Hawaii Community Foundation's Stronger Hawaii Fund and the Hawaiian Council's Kako’o Oahu program are collecting donations to assist affected households with housing and financial aid. Residents were encouraged to report damages to the city for assessment.