The flooding occurred during the Kona storm, Hawaii’s winter low-pressure system. The entire island is under a flood watch until the afternoon of March 22nd.
Kona storm causes flooding and road collapse across Maui
A powerful Kona storm flooded Maui and other Hawaiian islands, destroying roads and leaving thousands without power.
Catastrophic flooding continues to batter Hawaii as two consecutive storms batter the island with rain and wind.
Authorities said it was the worst flooding in the state in 20 years, with heavy rains washing away homes, damaging roads and threatening to burst dams.
Thousands of people were evacuated on the morning of March 20th due to a dam collapse on northern Oahu. The Hawaii Emergency Management Agency later said that while the 120-year-old dam had not collapsed, it was in “imminent danger of failure.”
Evacuations were ordered in Haleiwa and Waialua, and warnings were issued saying all roads were at risk of “imminent road closures.”
A warning appeared saying “Please leave now”.
Gov. Josh Green said there were no deaths or missing people from the flooding, but it was the worst the state had seen since the early 2000s. About 200 people were rescued from the floodwaters and about 10 were taken to hospital with hypothermia, he said.
“This is a huge threat to our people and to our state,” Greene said at a March 20 press conference.
On the morning of March 21, the National Weather Service in Honolulu announced that two systems are increasing the risk of rain (sometimes heavy rain of 2 to 4 inches per hour), thunderstorms, and flash flooding over the weekend. A flood watch was in place across the state until the afternoon of March 22nd.
The dam is located on central Oahu near Schofield Barracks off Kamehameha Highway. A gathering area had been set up for people who needed to evacuate or were unable to return home. According to USA TODAY’s dam tracking database, there are 13 dams on Oahu (Honolulu County). Seven of the cases are classified as having a “high” or “severe” potential risk. Wahiawa Dam is a privately owned dam built in 1906 and used primarily for irrigation. It is considered to be in poor condition and at high risk.
Water levels in the Kaukonawa River near Wailua, just northwest of the reservoir, rose more than 10.5 feet on March 20, and were several inches higher than they were on March 13, according to weather service data.
On March 20, the National Weather Service reported that a foot of water poured onto a road one mile east of Waialua, flooding several cars and homes. “The civilian had to be rescued and transported by bulldozer,” the bulletin said.
Kona Storm – Hawaii’s Winter Cyclone
A series of low pressure systems hit Hawaii in March. This is a winter phenomenon often referred to as the Kona Depression or Kona Storm, after the Hawaiian word “kona” meaning leeward. Winter storms typically affect the leeward side of the island, which is protected from trade winds and heavy rain, said Stephen Bassinger, a professor at the University of Hawaii’s meteorology department.
According to AccuWeather meteorologists, on average one or two Kona storms affect Hawaii between November and March, but it’s extremely rare for two to occur in the same month, much less within a week of each other.
The first round of storms affected the islands from March 10 to March 16, the newspaper said. Localized rainfall totals of more than 4 feet were produced.
Worst flood in 20 years
Green said the flooding in Hawaii was the worst the state had seen since the 2004 Manoa floods. The October 30, 2004 flood was one of several flash floods that occurred during a storm that brought heavy rain. Rainfall peaked at 1.29 inches in 15 minutes and 8.71 inches in 6 hours.
The Manoa River flooded in several areas. The worst of the flooding occurred when waves of water broke through residential areas and reached the University of Hawai’i at Manoa campus. According to the National Weather Service, flooding destroyed irreplaceable documents in the basement of the Hamilton Library and damaged several labs conducting important experiments.
No deaths or injuries were reported, but the damage amounted to approximately $85 million at the time. Approximately 120 homes were damaged and a pedestrian bridge over the Manoa River was destroyed.
Green said damages from the March 2026 floods could total $1 billion. This includes damage to numerous homes, roads, schools, airports and hospitals on Maui.
On the morning of March 20, a home on Kaihulo Drive in Mokuleia, near Waialua, was washed ashore by flash floods.
“It appears that the remains of the house were split in two and parts of the house collapsed,” according to a weather bureau storm report.
Separate storm reports said a section of road in Oahu’s Makaha Valley collapsed, sending vehicles over the edge and closing it in both directions on March 20.
