Torrential rain caused a dam in Hawaii to overflow on Monday, forcing the evacuation of about 150 households on the island of Maui and badly damaging or destroying at least half a dozen homes, the authorities said.
On Tuesday, after flooding on another island, Oahu, led to additional evacuation orders, Gov. David Ige declared a state of emergency, citing “extensive damage” across the state. The declaration will make state funds quickly available for those in need, he said.
An evacuation order, which remained in place on Tuesday, affected people who live downstream from the Kaupakalua Reservoir and Dam in the Haiku area of Maui, said Sandy Baz, the managing director of Maui County’s Department of Management.
Floodwaters destroyed one bridge in Haiku and heavily damaged a second bridge, Mayor Michael P. Victorino of Maui County said in a statement on Tuesday.
He described the flooding as “unprecedented,” and said officials would conduct damage assessments on Tuesday. “I ask everyone to stay vigilant and be safe,” he said.
At a news conference on Monday, Mr. Victorino said that the heavy rain had “created a very dangerous flooding situation throughout the county of Maui, but especially in east Maui.” He noted that at least five people had been rescued.
“Ladies and gentlemen, this is a real flooding situation we have not seen in a long time,” he said. Some residents, he added, had told him that it was the worst flooding they had seen in 25 years.
The evacuation order affected about 150 homes, according to The Honolulu Star-Advertiser. In a statement released on Monday, Maui County officials urged people not to return to the area “until it is safe to do so.”
As rains continued to pour on Tuesday, residents of Haleiwa Town, on the island of Oahu, to the north, were ordered to evacuate immediately. In a statement posted online, Honolulu’s Department of Emergency Management warned of “catastrophic flooding” and said: “YOU ARE IN DANGER. LEAVE NOW.”
On the island of Maui, evacuation shelters were opened at Paia Community Center and Hana High School, and the community center remained opened on Tuesday.
“Please stay at home and shelter in place,” said Mr. Victorino, who also urged visitors to the area to stay in their hotels or lodgings. “Do not go out,” he said.
A section of Hana Highway near the dam was closed on Monday as muddy water flooded the roadway. It has since reopened, according to the Hawaii Department of Transportation. About 1,300 customers in Haiku were without power on Tuesday morning, Mr. Victorino said.
The National Weather Service in Honolulu issued a flash flood watch for the Hawaii islands through Wednesday evening. Widespread rain showers were expected to continue on Tuesday evening as an upper-level disturbance interacted “with tropical moisture moving in from the south and east,” the Weather Service said.
Maui County officials initially thought that the dam had been breached by floodwaters, but “after closer inspection” they determined that “there was no structural damage,” the county said in a statement.
The land where the Kaupakalua Reservoir sits is owned by East Maui Irrigation, according to a statement from the office of Gov. David Y. Ige of Hawaii.
East Maui Irrigation is owned by Mahi Pono, a farming company, and Alexander & Baldwin, a real estate company. Shan Tsutsui, chief operating officer of Mahi Pono, said in a statement that “the dam did not fail.”
“While the levels exceeded peak capacity and caused over-topping of the dam yesterday afternoon, over-topping ceased in the early evening and has not reoccurred,” Mr. Tsutsui said in a statement on Tuesday. “We will continue to monitor the situation until it returns to a safe level.”
Constructed in 1885, the Kaupakalua dam is one of the oldest agricultural dams on Maui, according to the state. It is 57 feet high and 400 feet long, and can hold 68 million gallons of water.
Azi Paybarah contributed reporting.