After the largest flood Hawaiʻi has seen in 20 years, the state is facing $1 billion in estimated damages to public and private infrastructure, including schools, roads and homes, said Gov. Josh Green in a press conference Friday night.

Even as rainfall lessened for some parts of Oʻahu on Friday afternoon, state and county leaders warned residents to stay vigilant of flood risks and heavy rain through the weekend. So far, Green said the state has recorded no injuries or deaths associated with the storm and will remain under flood watch until Sunday evening.

“This is a serious storm,” the governor said. “The storm is not over.”

Flooding on the North Shore began early Friday morning and continued throughout the day, with residents seeking shelter at public schools and community parks in Central Oʻahu. The city opened five shelters and evacuation areas and sheltered fewer than 100 people there, Honolulu Mayor Rick Blangiardi said during Friday’s press conference.

Evacuation notices were lifted for residents from Kaʻena Point to Mokulēʻia around 5 p.m. on Friday but remained in place for Haleʻiwa and Waialua. While hundreds of residents evacuated, others said they were unable to leave their homes because of road closures. 

Honolulu Emergency Medical Services rescued dozens of people from Waialua and Wahiawā early Friday morning, as well as from a mental health hospital under the Queen’s Medical Center in ʻEwa Beach facing a flood risk later in the day, said Public Information Officer Shayne Enright in an emailed statement. More than 230 people in total were pulled out of treacherous conditions, the mayor said said.

All eyes were on the Wahiawā Dam, which the city said was facing an “imminent threat” of failure on Friday morning. At its peak, the dam’s water levels were just above 85 feet around 9 a.m. on Friday. Levels fell through the afternoon and were at just over 82 feet at the time of the press conference, although the city had warned that conditions could change quickly. The dam’s crest is at 88 feet.

“Additional areas of heavy rain are expected over the next few hours which could exacerbate existing flooding and cause additional rises in stream and reservoir water levels,” the city said in a flash flood warning issued in the early afternoon.

Already, some parts of Oʻahu have already seen 10 or more inches of rain, Green said on Friday evening. The island is expecting another 6 to 8 inches of rain in the next few days.

State officials have warned that the dam could flood for years, since the structure is not up to current safety standards. But the dam’s owner, Dole Food Co., has argued it doesn’t have enough money to fix it. 

During Friday’s press conference, Tony Koyamatsu from the Department of Land and Natural Resource’s Dam Safety Division said the department tested 122 dams in the state in recent weeks, with all of the structures operating “as designed.” Some dam operators opted to lower their levels in response to the incoming storm, Koyamatsu said, but he did not say if Dole was one of the owners that chose to do so.

The department has also tested emergency action plans with dam owners in the past year, he said.

Wahiawā District Court and state offices were closed on Friday as Green released state employees just before noon. Oʻahu schools also closed, although students were already scheduled to be on spring break until Monday. 

As of Friday afternoon, the Department of Education was still assessing the damage from last week’s storm on Haleʻiwa and Waialua schools and was determining if the campuses could safely open next week for classes, Communications Director Nanea Ching said.

As of Friday evening, more than 6,400 Oʻahu residents had lost power, according to HECO’s outage maps. The company had preemptively turned off power to around 4,100 customers on the North Shore on Friday morning at the request of fire officials, HECO said a press release. 

In other parts of the state, county officials braced for another weekend of heavy rain. Maui County is on flood watch through Sunday, with officials issuing evacuation advisories for East Maui, ʻĪao, parts of Lahaina and East Molokaʻi on Friday afternoon. 

Even if the rain is less severe, the county said, some of these areas are already vulnerable to flooding because of last week’s storm. The Maui County Council has already approved $12 million to cover damages from last week’s storm.