Manoa sustained the worst of Monday’s heavy downpours as streams overflowed and swept vehicles from parking lots, flooded homes and schools, and stretched already‑taxed emergency crews. Palolo and Nuuanu were among the other neighborhoods to also get hit hard.
After Green and Honolulu Mayor Rick Blangiardi toured devastated areas from Friday’s floods, the governor said the scale of destruction — particularly on Oahu’s North Shore — is shaping the state’s approach to Washington, D.C.
“When the mayor and I go in and do these walk-throughs and see people suffering on the North Shore, knowing that the feds are attentive, what we’re going to ask for is a positive thing,” Green said. The state will seek a 90% federal cost share for storm recovery, he said.
The flooding followed days of rain from a lingering Kona low that saturated watersheds statewide, leaving little capacity for additional runoff and causing rapid, destructive flooding in vulnerable valleys.
Green said state, county and federal teams are working in tandem to streamline assessments and avoid duplication.
“We also have FEMA now here, and they’re going to be doing the assessments so that we don’t have to do them twice,” Green said. “They’re going to do those assessments directly with the state guys.”
Green said the financial toll is expected to be significant statewide, with major infrastructure and housing losses already emerging. He pointed to the need to replace facilities such as Kula Hospital , along with major repairs to roads, airports and homes.
“It’s a big lift,” he said, noting that recovery costs alone for Kula Hospital likely will reach into the hundreds of millions of dollars.
The latest Kona-low system, the second to pummel the islands in two weeks, also flooded roads Monday on Hawaii island, which was under a flash-flood warning for much of Monday, followed by a flood watch late into the night.
However, Honolulu was no longer covered by even a flood watch Monday morning when the storm began to hit hard again in Windward and urban areas.
A flash-flood warning was reinstated Monday morning on Oahu and expired in the afternoon, but not before hours of heavy rain inundated urban Honolulu, with Manoa emerging as the most severely impacted community.
Heavy showers struck Windward Oahu Monday morning before spreading leeward, dumping intense rainfall over Manoa, Nuuanu and Palolo valleys. In Manoa, already-elevated streams quickly over topped their banks, sending water surging into residential streets, parking lots and commercial areas.
According to the National Weather Service, Nuuanu Reservoir No. 1 received 4 inches of rain in six hours ending at 4 p.m. , while Manoa’s Lyon Arboretum recorded more than 5 inches in the same period. The deluge followed over 6 inches of rain that fell between Thursday and Sunday, leaving drainage systems overwhelmed.
Floodwaters across urban Honolulu began to recede by late afternoon after inundating streets for most of the day.
The Honolulu Board of Water Supply began pumping water from Nuuanu Reservoir No. 1 to reduce water levels, triggering the closure of the far-right townbound lane of the Pali Highway between Waokanaka Street and Country Club Road.
BWS separately urged residents from Honokai Hale to Makaha to limit water use to essential needs, citing strain on the system.
Blangiardi said the city is mobilizing across agencies as crews respond to storm damage islandwide, with resources already strained by impacts in multiple areas, including the North Shore and Manoa.
“Given the unprecedented scale and scope of this, (it) is all hands on deck across the board, and we’ll try to prioritize where the greatest needs are,” Blangiardi said, adding that the city will continue deploying personnel where conditions are most severe.
He acknowledged that response efforts will be stretched as new flooding incidents emerge.
“So we’ll be stretched, too,” he said, noting the challenges facing residents dealing with direct impacts.
Blangiardi said officials are working to ensure communities feel supported during the emergency response.
“There’s one of those points in time when we don’t want anybody … to say, nobody helped us, we don’t want that.”
The Monday deluge sent Manoa Stream surging into surrounding neighborhoods and commercial areas, flooding parts of Woodlawn Drive , damaging property and rekindling long-standing concerns about flood preparedness in the valley.
Vehicles were seen floating, colliding with one another and later left stalled, coated in mud and debris.
At the University of Hawaii at Manoa Innovation Center, 22-year-old student Kolby Kaneshiro returned from lunch to find that his car had floated across the lot, carried by rising floodwaters.
Businesses at Manoa Marketplace were largely spared, though flooding hit the back side along Woodlawn Drive . The Longs Drugs Manoa location closed around 2 p.m., but was not directly impacted by floodwaters.
Jonathan Loui, an employee at Brug Bakery, said the storm did not initially raise alarms. He arrived at work around 6:30 a.m. , and by late morning noticed heavy rain but assumed it was typical given recent weather.
“There was strong rain, I could see all of it outside, but it’s been raining pretty hard the past couple weeks so I kind of just disregarded it,” Loui said. “It looked completely fine but then customers were telling me that there was heavy flooding so that’s how I found out about it.”
Two weeks earlier, during a Kona-low storm, Manoa Marketplace — including Brug — lost power. Loui said he did not expect Monday’s storm to cause significant problems.
Several Manoa residents said Monday’s flooding brought back memories of the Oct. 30, 2004, storm that caused widespread destruction after Manoa Stream overflowed, damaging University of Hawaii buildings and nearby neighborhoods.
“This was the closest call since 2004,” said Glenn Otaguro, who lives near Manoa Gardens senior housing with the stream directly behind his home.
“I experienced an almost flooding incident,” Otaguro said. “If it had been a little bit worse or higher, it would have been the same flood we had in 2004 that flooded our neighborhood.”
Otaguro said rain fell steadily from about 11 a.m. to 2 p.m., at times coming down “like cats and dogs,” overwhelming drainage systems. Water pooled several inches deep outside his home and began seeping under a door.
“The patio was the first thing I worried about because that’s what flooded in 2004,” Otaguro said. “I didn’t want to open the door and bring more water in.”
He deployed six or seven sandbags to hold back the water.
The stress of Monday’s storm carried added weight for Otaguro, who has lived in the family home for more than 60 years. After the 2004 flood, during which he helped clean mud and debris from his parents’ home, Otaguro suffered a heart attack about two months later.
“That event was extremely stressful, and today was stressful too,” he said. “Putting out sandbags under pressure, worrying if the water’s going to rise — it brings it all back.”
Liane Qimura-Rita said the stream behind her home, which is across the street from the Manoa Marketplace , surged by an estimated 15 feet, pushing large albizia trees into her property.
“It was totally unexpected because the stream rose really fast,” she said. “Huge trees are lodged in our garage — the garage level is trashed.”
Floodwaters rose about 5 feet inside her garage before receding, leaving behind debris and damage that will require heavy machinery to clear. No injuries were reported.
Qimura-Rita and Otaguro said Monday’s storm highlighted ongoing concerns about flood warnings and mitigation.
“There was no flood watch or advisory early,” Otaguro said. “The warning came at least an hour after the rain started.”
He said radar showed intense rainfall quickly
forming over the Koolau mountains and stalling above Manoa.
“The clouds just parked on top of the Koolaus,” he said.
Both Otaguro and Qimura-Rita pointed to the need for long-delayed flood control efforts in the Ala Wai watershed.
He favors the city’s proposed plan to charge a Storm Water Utility Fee based on their amount of impervious surface area.
Qimura-Rita said that she hopes the flooding will renew momentum for the long-stalled Ala Wai Canal Flood Risk Management Project , which she said would have included storm walls extending to her property as part of broader mitigation efforts across the Ala Wai watershed.
“If that watershed effort can get kick-started from this, that would be the saving grace,” she said. “If it doesn’t, this will happen again.”
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