Flash Flood Warning Extended for Kauai as Heavy Rain Swells Rivers and Closes Highway

The National Weather Service has extended a flash flood warning for Kauai through the early evening as heavy rain continues to drench the eastern slopes of the Hawaiian island, forcing the closure of a major highway and raising concerns about rapid river rises and dangerous marine conditions.

The updated warning, issued shortly after 3:10 p.m., keeps the alert in effect until 5:45 p.m. and cites rainfall rates of up to 1 to 2 inches per hour. Forecasters say flash flooding is already underway or expected to begin shortly along the Kuhio Highway near the Hanalei Bridge and near the mouth of the Wailua River, while a separate marine statement warns boaters near Niihau to prepare for waterspouts, gusty winds and blinding downpours.

COURTESY NWS — Heavy rain has prompted a flash flood warning for Kauai this afternoon.

NWS Extends Flash Flood Warning Until Early Evening

The National Weather Service in Honolulu extended the flash flood warning for Kauai until 5:45 p.m., updating an earlier advisory that had originally been set to expire at 2:45 p.m. According to the latest bulletin, Doppler radar and automated rain gauges detected heavy rain over the eastern slopes of Kauai at 2:19 p.m., with additional showers moving in from the southwest. Rainfall rates reached as high as 1 to 2 inches per hour.

In addition to the Hanalei River, forecasters observed a rapid rise along the South Fork of the Wailua River. Flash flooding is ongoing or expected to begin shortly, especially near the Hanalei Bridge on the Kuhio Highway and near the mouth of the Wailua River.

Kuhio Highway Closed at Hanalei Bridge Amid Rising Floodwaters

Kuhio Highway near the Hanalei Bridge was closed due to floodwaters at approximately 12:45 p.m., and remained shut down as of the latest update. The closure cuts off a key route along Kauai’s north shore and underscores the immediate danger to motorists.

Forecasters warned the public to expect flash flooding of small creeks and streams, urban areas, highways, streets and underpasses, as well as other locations with poor drainage or low-lying terrain. Drivers are advised to avoid flooded roadways and seek alternate routes until the warning expires.

Marine Statement Warns of Waterspouts and Gusty Winds Near Niihau

In addition to the flash flood warning, the National Weather Service issued a special marine statement for Kauai’s leeward waters, cautioning of waterspouts and wind gusts of 34 knots or greater until 4:30 p.m. At 2:23 p.m., forecasters located a strong weather system capable of producing waterspouts roughly 10 nautical miles southwest of the southern tip of Niihau — or about 39 nautical miles southwest of Barking Sands — moving east at 10 knots. The southern tip of Niihau is among the locations that may be impacted.

Boaters were urged to prepare for gusty winds, steep and fast-building seas and blinding downpours, staying low or going below deck and ensuring that everyone on board wears a life jacket.

Broader Weather Pattern Brings Showers to Kauai and Oahu

The heavy rain on Kauai is part of an approaching disturbance expected to trigger a few heavy showers through the afternoon and tonight, mainly over Kauai and Oahu. Meteorologists say the tail end of a front will move down the island chain late Sunday through Monday, ushering in breezy northeasterly trades and drier air. In the meantime, breezy easterly trades are expected to bring periods of windward and mauka showers through the rest of the week.

Safety Precautions for Drivers and Residents

Residents and visitors should monitor official National Weather Service updates and avoid driving through flooded streets or underpasses. Even seemingly shallow water can conceal washed-out roads or swift currents, and flash flooding can develop quickly in urban and low-lying areas. Those on the water near Kauai and Niihau should heed the marine statement, secure loose gear and remain alert for rapidly changing visibility and sea conditions.

Distant Pacific System Could Develop Into Tropical Cyclone Next Week

Farther afield, forecasters at the National Hurricane Center in Miami are monitoring a weather system far southeast of the Hawaiian Islands in the East Pacific. The system currently has a 40 percent chance of developing into a tropical cyclone by the end of next week. If it strengthens as projected, it could gradually become a tropical depression late next week as it moves west-northwest into the Central Pacific and toward Hawaii. Officials said it is too early to determine any direct impacts on the islands, but the system bears watching as the week progresses.

Drier Trade Winds Expected to Return by Monday

Looking ahead, the boundary bringing this weekend’s unsettled weather is forecast to lose strength as it moves south. By late Sunday and Monday, drier air and breezy northeasterly trade winds are expected to return, gradually clearing out the wet weather. Until then, Kauai and Oahu remain under the threat of additional heavy showers and localized flooding.

For now, the immediate focus remains on Kauai’s flooded roadways and swollen rivers. With the flash flood warning running into the early evening and marine hazards persisting near Niihau, officials are urging caution on the roads and on the water. A return to drier trade-wind weather is on the horizon, but residents and visitors should stay alert through the weekend as the current system moves through.

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