Surprise Downpour Sends Floodwaters Through Honolulu Neighborhoods, Recovery Underway

Reddish-brown torrents were still coursing through streets in Honolulu's Manoa Valley on Tuesday as crews fanned out across Oahu to evaluate the latest round of destruction, adding a new chapter to what has become the worst flooding Hawaii has seen in more than two decades.

Crews on Tuesday began evaluating damage from a surprise downpour that sent floodwaters raging through a neighborhood near downtown Honolulu, the latest bout in a series of storms and flooding that have pummeled the state over the past two weeks. The timing was brutal: residents along Oahu's North Shore were still cleaning up from that worst flooding when a storm Monday unleashed several inches of rain on the southern part of the island.

Reddish-brown torrents gushed along roads in the Manoa Valley, a few miles east of downtown Honolulu, sweeping away parked cars and swamping much of the neighborhood. Manoa Stream rose rapidly, jumping from about 3 feet to 12 feet, contributing to widespread flooding in nearby neighborhoods, and floodwaters submerged vehicles along East Manoa Road and Oahu Avenue, forcing temporary road closures. "I was shocked to see how much flash flooding there was in my area," said resident Andrew Phomsouvanh, who recorded video of streets transformed into a confluence of rapids.

Honolulu Mayor Rick Blangiardi called it a "classic rain bomb," and said that earlier in the day, the skies were sunny. "We had no warning," he said Tuesday as he toured the damage.

The Monday downpour struck a city already battered and saturated. The Kona low drenched soil already saturated by downpours from a similar low pressure system a week earlier, compounding what officials described as Hawaii's worst flooding in more than 20 years. The downpour, which dumped 2 to 4 inches of rain per hour, was highly localized, catching even meteorologists off guard.

The cumulative toll from the series of storms is staggering. Evacuation orders covered 5,500 people north of Honolulu, and some residents fled on surfboards as water reached waist or chest high. There were no immediate reports of deaths or serious injuries, but authorities said hundreds of homes on Oahu's North Shore had been damaged by last week's flooding. More than 230 people had to be rescued. The water pushed houses off their foundations, floated cars out of parking spots and left walls, floors and counters covered with thick, reddish volcanic mud.

Farms around the state reported more than $9.4 million in damage as of Monday, according to a survey conducted by Agriculture Stewardship Hawaii, the Hawaii Farm Bureau and other organizations. Even before Monday's downpour, Gov. Josh Green said the cost of the storm could top $1 billion, including damage to airports, schools, roads, homes and a Maui hospital in Kula. Green's office said Tuesday he had submitted a major disaster declaration request to the Trump administration.

Mayor Blangiardi said the City and County of Honolulu will establish sites where affected residents can dump storm debris as they clean up their properties, and the county will waive dump tipping fees and permit requirements for the time being. Aloha United Way CEO Michelle Bartell said residents are encouraged to call United Way's help line at 211 to connect with available resources.

The storms responsible for the widespread flooding are known as Kona lows, low-pressure weather systems that usually form in the winter months and bring heavy rain and strong winds. Two such systems have struck in the span of two weeks, and experts say the intensity and frequency of heavy rains in Hawaii have increased amid human-caused global warming. Some areas statewide saw 15 to 25 inches of rain over the past five days, according to the National Weather Service, and while conditions are expected to gradually improve, forecasters cautioned that even modest additional rainfall could quickly trigger flooding on ground still far too saturated to absorb it.