Severe rainfall triggered widespread flooding across parts of Oahu, Hawaii inundating streets, displacing homes, submerging vehicles, and forcing thousands of residents in communities north of Honolulu to evacuate on Friday.
Authorities also raised alarm over the potential failure of the aging Wahiawa Dam, a structure more than a century old.
Emergency sirens echoed across the island’s North Shore as floodwaters surged through areas known globally for surfing. Officials in Honolulu urged residents living downstream of the Wahiawa dam to leave immediately, warning the structure was “at risk of imminent failure.”
More than 230 individuals were rescued as relentless rainfall battered the island, causing what authorities described as the worst flooding in two decades. Governor Josh Green said the destruction could exceed $1 billion in damages.
Although water levels at the dam have begun to decline, officials cautioned that additional rainfall could quickly reverse the trend. Within a 24-hour period, water levels rose from 79 feet to 84 feet—just six feet below maximum capacity.
No fatalities were recorded, and all residents have been accounted for, according to Gov. Green. However, approximately 10 individuals were hospitalised for hypothermia.
Search and rescue operations were carried out both by air and water to reach stranded residents, though officials said these efforts were complicated by individuals flying private drones to capture footage of the disaster.
Honolulu Mayor Rick Blangiardi reported that dozens, if not hundreds, of homes sustained damage, though the full scale of destruction remains unclear. Around 5,500 residents were placed under evacuation orders.
“There’s no question that the damage done thus far has been catastrophic,” he said.
Blangiardi noted that while authorities are confident in the structural integrity of dams across the island, unpredictable rainfall patterns make the situation difficult to assess.
Emergency responders, including the National Guard and Honolulu Fire Department, evacuated 72 children and adults attending a spring break camp at Our Lady of Kea’au on the island’s west coast. Although the site is located on elevated ground, officials opted to relocate the group as a precaution.
Kimberly R.Y. Vierra, spokesperson for St. Francis Healthcare System of Hawai‘i, which owns the retreat, said floodwaters had cut off the only access road to the facility.
On Maui, evacuation advisories were issued for parts of Lahaina after nearby retention basins approached capacity. The affected areas include neighborhoods still recovering from the devastating 2023 wildfire.
Authorities have been closely monitoring dam conditions since a previous storm last week caused severe flooding that destroyed homes and roads, leaving two people seriously injured. Another storm system, though expected to be weaker, is forecast to bring additional rainfall through the weekend.
“It’s going to be a very touch-and-go day,” Hawaii Gov. Josh Green said in a social media post.
Much of the state remained under a flood watch, with Haleiwa and Waialua under a flash flood warning, according to the National Weather Service.
Flooding also forced the evacuation of a shelter at Waialua High and Intermediate School, where about 185 people and 50 pets had been staying. Authorities arranged transportation to relocate them, though by midday, 54 people remained at the site.
Parts of Oahu recorded between 8 and 12 inches (20 to 30 cm) of rainfall overnight, compounding the effects of earlier storms. Mount Kaʻala, the island’s highest point, received nearly 16 inches (40 cm) of rain within 24 hours, according to the National Weather Service.
Meteorologists attributed the heavy downpours to winter storm systems known as “Kona lows,” which draw in moisture-rich air from the south or southwest. Experts have also linked the increasing frequency and severity of such events to human-driven climate change.
As evacuation efforts continued, Waialua resident Kathleen Pahinui expressed concern about the dam’s condition, noting its vulnerability during heavy rainfall.
“Just pray for us,” she said. “We understand there’s more rain coming.”
State officials have previously classified the Wahiawa dam as having a “high hazard potential,” warning that a failure could likely result in loss of life. Constructed in 1906 to support sugar production for the Waialua Agricultural Company—later a subsidiary of Dole Food Company—the dam was rebuilt after a collapse in 1921.
Records show the state has issued multiple deficiency notices to Dole since 2009 and fined the company $20,000 five years ago for failing to address safety concerns in a timely manner.
Dole later предложed transferring ownership of the dam and related infrastructure to the state in exchange for government-funded repairs to bring it up to safety standards.
In 2023, Hawaii lawmakers approved legislation to acquire the dam, allocating $5 million for the spillway purchase and $21 million for upgrades. However, the transfer process remains incomplete, with a state board expected to vote on the acquisition next week.
“The dam continues to operate as designed with no indications of damage,” Dole said in an emailed statement.
According to a 2019 report by the American Society of Civil Engineers, Hawaii oversees 132 dams statewide, most originally built to support irrigation for the sugar industry.
