Hawaii’s Worst Flooding in 20 Years Leaves Thousands Without Power as Damage Could Top $1 Billion
Hawaii is experiencing its worst flooding in 20 years after consecutive storms dumped as much as nearly 16 inches in parts of Oahu, prompting evacuation orders for roughly 4,000–5,500 people, activation of the National Guard, airlifts and hundreds of rescues as officials warned the 120‑year‑old Wahiawa Dam was at risk of imminent failure. Thousands remained without power, shelters flooded and infrastructure was heavily damaged—Gov. Josh Green estimates total storm costs could top $1 billion—though officials report no deaths so far and continue to monitor the dam and forecast more rain.
📌 Key Facts
- Honolulu issued a 5:35 a.m. emergency alert ordering more than 4,000 people downstream of the 120‑year‑old Wahiawa Dam to evacuate after officials warned the dam was “at risk of imminent failure” and water was running over the spillway; broader evacuation orders at the peak affected roughly 5,500 people north of Honolulu (those earlier orders have since been lifted).
- Wahiawa Dam levels rose from about 79 to 84 feet overnight (roughly 6 feet below maximum) and were closely monitored; fears of imminent failure largely eased as water levels later dropped, though the dam remains under surveillance.
- Extremely heavy rain — Kaala peak recorded nearly 16 inches in a day and many north‑Oahu areas saw 8–12 inches overnight — produced "widespread life‑threatening flash flooding" in places such as Haleiwa and Waialua; forecasters initially warned of another 6–8 inches over 2–3 days before conditions shifted to scattered showers.
- Floodwaters pushed homes off foundations, swept away some houses and vehicles, and forced large‑scale rescues: officials say more than 200 people were rescued, the National Guard and Honolulu Fire Department airlifted 72 children and adults from a youth camp, and roughly 185 people and 50 pets had to be moved when a school shelter flooded.
- Officials reported no deaths or missing persons so far; at least about 10 people were taken to hospitals for hypothermia.
- Utilities and outages: more than 2,000 customers remained without power Sunday afternoon; Hawaiian Electric had proactively shut off about 1,200 customers in Waialua (service there has been restored), roughly 100 customers remained out in Maui County, and the utility expected to restore service to about 2,000 more customers.
- Public‑health and reporting measures: a boil‑water notice remained in effect for North Shore areas from Mokuleia to Turtle Bay, and residents were urged to report property damage to local authorities.
- Economic and climate context: Gov. Josh Green called this the most serious flooding in Hawaii since the 2004 Manoa floods and now estimates total storm costs could top $1 billion (including damage to airports, schools, roads, homes and a Maui hospital in Kula); officials noted the floods followed back‑to‑back Kona low systems and experts say heavy‑rain intensity and frequency in Hawaii are increasing due to human‑caused climate change.
- Search‑and‑rescue operations were hindered at times by civilians flying personal drones over the flood zone, which interfered with aerial missions; firefighters and lifeguards on jet skis were also conducting water searches for stranded people.
📊 Relevant Data
In Urban Honolulu, 11.4% of the population lives below the poverty line, with 82.3% of those in poverty belonging to marginalized racial and ethnic groups, including 29.9% Native Hawaiian, 24.2% Native American, 15.2% Black, and 13% Hispanic or Latino, and high-poverty areas are concentrated within 5 miles of the shore, increasing vulnerability to flooding and sea level rise.
Disparities in Impacts of Sea Level Rise in Under-Resourced Communities — University of Hawaii at Manoa ScholarSpace
The North Shore of Oahu has a resident population of 29,027, with a racial composition of 31.1% White, 15.2% Asian, 15.4% Native Hawaiian/Pacific Islander, 24.3% two or more races, and 10.4% Hispanic, featuring higher proportions of Native Hawaiians and Pacific Islanders compared to the statewide average of 9.7%.
Oahu's North Shore Economic Profile — Hawaii Department of Business, Economic Development & Tourism
The number of floods per year in Hawaii has increased sharply since the 1960s, with expectations of further increases due to climate change, alongside an increase in consecutive days of extreme heavy rainfall contributing to more runoff, erosion, and flooding.
Less & Heavy Rain — Hawaii Climate Change Portal
📰 Source Timeline (5)
Follow how coverage of this story developed over time
March 23, 2026
6:30 AM
Historic Hawaii floods leave 2,000 people without power
New information:
- More than 2,000 people remained without power Sunday afternoon, down from earlier outages, with Hawaiian Electric expecting to restore service to about 2,000 more customers later Sunday.
- Hawaiian Electric had proactively shut off power to about 1,200 customers in Waialua on Oahu’s North Shore on Friday and has since restored service there; roughly 100 customers remain without power in Maui County and all major outages on Hawaii Island have been addressed.
- Officials say more than 200 people were rescued during the flooding and that earlier evacuation orders for roughly 5,500 people north of Honolulu have been lifted, with no deaths reported so far.
- Gov. Josh Green now estimates total storm costs could top $1 billion, including damage to airports, schools, roads, homes and a Maui hospital in Kula.
- A boil-water notice remains in effect for North Shore areas from Mokuleia to Turtle Bay, and residents are urged to report property damage to local authorities.
- Meteorologist Matthew Foster says the worst of the storm is over, with rainfall now shifting to scattered showers and less than 5 inches of rain expected on Hawaii Island and 1–2 inches elsewhere, and more typical March weather expected by Wednesday.
- Authorities say earlier fears that the 120-year-old Wahiawa Dam could fail have largely eased as water levels have dropped, though the dam continues to be monitored.
- The article reiterates that the flooding followed back-to-back 'Kona low' systems and notes experts’ assessment that heavy-rain intensity and frequency in Hawaii are increasing due to human-caused climate change.
March 21, 2026
7:55 AM
Hawaii suffers its worst flooding in 20 years and forecasters warn more rain is coming
New information:
- Gov. Josh Green calls this Hawaii’s most serious flooding since the 2004 Manoa floods and estimates total storm costs could top $1 billion, including damage to airports, schools, roads, homes and a Maui hospital in Kula.
- Authorities report roughly 5,500 people under evacuation orders north of Honolulu, with at least about 10 people taken to a hospital for hypothermia and no deaths or missing persons so far.
- Officials say Oahu’s Kaala peak received nearly 16 inches of rain in a day, other parts of Oahu saw 8–12 inches overnight, and additional 6–8 inches are forecast over the next two to three days.
- The Wahiawa Dam level rose from 79 to 84 feet overnight, about 6 feet below its maximum, before receding somewhat, and is being closely watched for possible failure as more rain is expected.
- The National Guard and Honolulu Fire Department airlifted 72 children and adults from the Our Lady of Kea’au spring break youth camp on Oahu’s west coast as a precaution, even though the camp sits on high ground.
- Honolulu officials report that search and rescue efforts were hampered by civilians flying personal drones over the flood zone, interfering with aerial operations.
March 20, 2026
9:35 PM
Over 4,000 told to evacuate flooding in Hawaii as officials warn 120-year-old dam could fail
New information:
- Honolulu officials say emergency sirens blared along Oahu’s North Shore as muddy floodwaters pushed homes off their foundations, swallowed vehicles and swept away some houses, though the exact number is not yet known.
- Honolulu’s 5:35 a.m. evacuation order covers more than 4,000 people downstream of the 120‑year‑old Wahiawa Dam, with officials warning it is "at risk of imminent failure" and water is actively running over the spillway.
- Roughly 185 people and 50 pets sheltering at Waialua High and Intermediate School had to be relocated by bus after that shelter flooded, amid 8–12 inches of overnight rain and what NWS calls "widespread life‑threatening flash flooding" in Haleiwa and Waialua.
- Gov. Josh Green says the Hawaii National Guard has been activated and describes chest‑high floodwaters on parts of northern Oahu, calling it a "very touch‑and‑go day," while a state senator says some residents are effectively isolated and unable to evacuate due to high water.
9:04 PM
Officials warn 120-year-old Hawaiian dam could fail as thousands told to evacuate flooding
New information:
- Honolulu officials issued a specific 5:35 a.m. emergency alert Friday telling residents downstream of Wahiawa Dam to evacuate because it was 'at risk of imminent failure.'
- Honolulu Department of Emergency Management spokesperson Molly Pierce said the evacuation order covers more than 4,000 people and confirmed that 'water is actively running over the spillway right now.'
- City spokesperson Ian Scheuring said firefighters and lifeguards on jet skis are searching floodwaters for stranded people and that there are reports of homes being swept away, though the total is not yet known.
- Roughly 185 people and 50 pets sheltering at Waialua High and Intermediate School had to be evacuated and bussed to another center because that shelter itself flooded.
- Officials reported 8 to 12 inches of rain overnight in parts of north Oahu, on top of catastrophic flooding from last week’s storm, with the National Weather Service warning of 'widespread life-threatening flash flooding' particularly in Haleiwa and Waialua.