Over 5,500 told to evacuate flooding in Hawaii as officials warn 120-year-old dam could fail

A surfer walks out of the ocean on Oahu's North Shore near Haleiwa, Hawaii, March 31, 2020. (AP Photo/Caleb Jones)

HONOLULU — Muddy floodwaters from severe rains inundated streets, pushed homes off their foundations, swallowed vehicles and prompted evacuation orders for thousands of residents in towns north of Honolulu on Friday as officials warned of the possible failure of a 120-year-old dam.

Emergency sirens blared along Oahu’s North Shore, where rising waters damaged homes in a community world-renowned for its surfing. Honolulu officials told residents Friday morning to leave the area downstream of Wahiawa dam -- long known to be vulnerable -- saying it was “at risk of imminent failure.”

There were no immediate reports of deaths or injuries, but some homes had been swept away, said Ian Scheuring, a spokesperson for Honolulu. Crew searched by air and by water for people who had been stranded -- efforts that were hampered by people flying personal drones to get images of the flooding, he said.

Dozens -- if not hundreds -- of homes had been damaged but officials have not been able to fully assess the destruction, Honolulu Mayor Rick Blangiardi said in an afternoon news conference. Some 5,500 people were under evacuation orders.

“There’s no question that the damage done thus far has been catastrophic,” he said.

Blangiardi said officials felt confident in the stability of the dams on the island, but that it was hard to predict how much rain would come and what it might do.

The National Guard and Honolulu Fire Department airlifted 72 children and adults who had been attending a spring break youth camp at a retreat on Oahu’s west coast called Our Lady of Kea’au, according to city and camp officials. The camp is on high ground but authorities didn’t want to leave them there, the mayor said.

Kimberly R.Y. Vierra, a spokesperson for St. Francis Healthcare System of Hawai`i, which owns the retreat property in west Oahu, said floodwaters had cut off the entrance road to the camp.

On Maui, officials issued an evacuation advisory for some Lahaina neighborhoods after nearby retention basins neared capacity. Parts of those neighbourhoods were burned by the massive wildfire that destroyed much of Lahaina in 2023.

Officials have been watching dam levels since a storm last week dumped heavy rain across the state, which led to catastrophic flooding that washed away roads and homes. After the worst of it, a similar but weaker storm was forecast to bring more rain through this weekend.

“It’s going to be a very touch-and-go day,” Hawaii Gov. Josh Green said in a social media post.

Most of the state was under a flood watch, with Haleiwa and Waialua in northern Oahu under a flash flood warning, according to the U.S. National Weather Service.

One shelter at Waialua High and Intermediate School was evacuated because of flooding, Scheuring said. There were about 185 people and 50 pets there who needed to be bussed to another evacuation center, but by midday 54 people still remained in the shelter.

Parts of Oahu received eight to 12 inches (20 to 30 cm) of rain overnight, further saturating the ground after the storm last weekend. Kaala, the island’s highest peak, got nearly 16 inches (40 cm) in the past day, NWS said.

Winter storm systems known as “Kona lows,” which feature southerly or southwesterly winds that bring in moisture-laden air, were responsible for the deluges. The intensity and frequency of heavy rains in Hawaii of have increased amid human-caused global warming, experts say.

As she prepared to evacuate to a friend’s home on higher ground, Waialua resident Kathleen Pahinui told The Associated Press in a phone interview that the aging Wahiawa dam is a concern every time it rains.

“Just pray for us,” she said. “We understand there’s more rain coming.”

The state has said the dam has “high hazard potential,” and that a failure “will result in probable loss of human life.”

The earthen dam was built in 1906 to increase sugar production for the Waialua Agricultural Company, which eventually became a subsidiary of Dole Food Company. It was reconstructed following a collapse in 1921.

The state has sent Dole four notices of deficiency about the dam since 2009 and five years ago fined the company US$20,000 for failing to address safety deficiencies on time, according to records.

Afterward, Dole proposed to donate the dam, reservoir and ditch system to the state in exchange for the state’s agreement to repair the spillway to meet and maintain dam safety standards.

The state passed legislation in 2023 authorizing the dam’s acquisition. It also provided US$5 million to buy the spillway and US$21 million to repair and expand it to comply with dam safety requirements. But the transfer has not been completed. A state board is due 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.

The state regulates 132 dams across Hawaii, most of them built as part of irrigation systems for the sugar cane industry, according to a 2019 infrastructure report by the American Society of Civil Engineers.

By Jennifer Sinco Kelleher.