Hawaii flash floods wreak havoc as 120-year-old dam threatens to burst, 230 people rescued

Severe rains caused muddy floodwaters to engulf streets, displace homes, and submerge vehicles, leading to evacuation orders for thousands north of Honolulu on Friday. Officials raised alarms over the potential failure of a 120-year-old dam.

Emergency sirens echoed along Oahu’s North Shore, where homes in a renowned surfing community suffered damage from rising waters. Honolulu officials urged residents Friday morning to evacuate the area downstream of the vulnerable Wahiawa dam, warning it was “at risk of imminent failure.”

Over 230 individuals were rescued as Oahu faced its worst flooding in 20 years, with the governor estimating damages could exceed $1 billion.

While water levels at the dam, which authorities cautioned could fail, have been receding, they remain precariously close to capacity. Within 24 hours, levels rose from 79 feet to 84 feet, just six feet shy of the dam’s limit, according to officials.

Governor Josh Green reported no deaths or missing persons at a news conference, though about 10 people were hospitalized with hypothermia.

Rescue crews searched by air and water for stranded individuals, but efforts were impeded by people using personal drones to capture images of the flooding.

Although dozens, if not hundreds, of homes were damaged, officials have yet to fully assess the destruction, said Honolulu Mayor Rick Blangiardi in an afternoon briefing.

Approximately 5,500 residents were placed under evacuation orders.

“The damage done thus far has been catastrophic,” Blangiardi stated.

Though confident in the dams’ stability, Blangiardi noted the unpredictability of further rain and its potential impacts.

The National Guard and the Honolulu Fire Department airlifted 72 children and adults from a spring break youth camp at Our Lady of Kea’au on Oahu’s west coast. Despite the camp’s high ground, authorities preferred not to risk leaving them there.

Kimberly R.Y. Vierra, a spokesperson for St. Francis Healthcare System of Hawai‘i, which owns the retreat property, mentioned that floodwaters blocked the camp’s entrance road.

On Maui, evacuation advisories were issued for some Lahaina neighborhoods, as nearby retention basins approached capacity. These areas were previously affected by a massive wildfire in 2023.

Officials have been monitoring dam levels since a storm last week caused catastrophic flooding, washing away roads and homes. Two people sustained serious injuries during that event, and a weaker storm is expected to bring more rain over the weekend.

“It’s going to be a very touch-and-go day,” Governor Green remarked on social media.

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

Flooding forced the evacuation of a shelter at Waialua High and Intermediate School, stated Ian Scheuring, a spokesperson for Honolulu. Although 185 people and 50 pets needed relocation, 54 individuals remained at the shelter by midday.

Some areas of Oahu received 8 to 12 inches of rain overnight, further saturating the land following last weekend’s storm. Kaala, the island’s highest peak, recorded nearly 16 inches in the past day, according to the NWS.

Winter storm systems, known as “Kona lows,” characterized by southerly or southwesterly winds bringing moisture-laden air, were attributed to the heavy rains. Experts indicate that human-caused global warming is increasing the intensity and frequency of such rains in Hawaii.

Waialua resident Kathleen Pahinui, preparing to evacuate, expressed concerns to The Associated Press about the aging Wahiawa dam during rainy periods.

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

The state has labeled the dam as having “high hazard potential,” indicating that failure could likely lead to loss of human life.

The earthen dam, constructed in 1906 to boost sugar production for the Waialua Agricultural Company, now a Dole Food Company subsidiary, was reconstructed after collapsing in 1921.

Since 2009, the state has issued Dole four deficiency notices regarding the dam and fined the company $20,000 five years ago for delayed safety improvements.

Subsequently, Dole offered to donate the dam, reservoir, and ditch system to the state in exchange for state-funded spillway repairs to meet dam safety standards.

In 2023, legislation was passed to authorize the dam’s acquisition, allocating $5 million for purchasing the spillway and $21 million for repairs and expansion to meet safety requirements. However, the transfer remains incomplete, with a state board scheduled to vote on the acquisition next week.

“The dam continues to operate as designed with no indications of damage,” Dole stated in an email.

The state oversees 132 dams across Hawaii, primarily constructed for sugar cane irrigation systems, according to a 2019 report by the American Society of Civil Engineers.