Big Island under flood watch as heavy rain threatens through Saturday
A flood watch covered the Big Island through Saturday morning, with forecasters warning that some areas could see more than 10 inches of rain and flash flooding.
The Big Island was under a flood watch after heavy rain threatened to soak Hawaii Island through 6 a.m. Saturday, with the National Weather Service warning that flash flooding was possible across Kona, Kohala, the Big Island Interior, the summits, and the south, southeast, east and north districts.
The watch was issued Friday at 2:17 p.m. HST by the National Weather Service Honolulu Forecast Office. Forecasters said an upper-level low and an associated surface boundary were driving the rain, and warned that flood-prone roads and other low-lying areas could close as runoff rose and streams overflowed. Urban areas faced the added risk of faster runoff, which can turn a hard downpour into property damage within minutes.
Hawaii County said some models showed parts of the island could receive more than 10 inches of rain. County Civil Defense urged residents to sign up for emergency alerts and prepare for power outages, flooding and travel disruptions, especially in areas that already struggle when drainage systems are overwhelmed.
The county’s alert system uses Everbridge to send notices by email, text message and recorded phone calls. Residents can also opt in by texting HAWAIIALERTS to 888777. Those warnings mattered because the same weather pattern had already dumped 4 to 7 inches of rain in parts of Oahu and triggered flash flooding there before the disturbance began to weaken.
Forecasters said the upper-level disturbance was expected to weaken Saturday, which would reduce heavy-rain chances across most islands. Even so, wet easterly trade winds were expected to keep showers going on windward and southeast Big Island slopes into early next week, leaving the island vulnerable to additional runoff after the main band of rain passed.
The concern was sharpened by what happened during a March 2026 Kona low. Flooding on Highway 11 in Kaū isolated Wood Valley, Pāhala, Nāālehu, Green Sands Subdivision and the Haao Springs Road/Waiohinu area. County officials said some areas in Kaū received 10 to 15 inches of rain in 24 hours. Shelter openings at Nāālehu Community Center, Robert N. Herkes Gym in Pāhala and Cooper Center in Volcano followed, and Hawaii Fire Department rescued three residents from a flooded home near Whittington Beach Park.
That earlier storm showed how quickly saturated ground can turn dangerous on the Big Island. With another round of heavy rain in the forecast, officials again warned that back-to-back storms can erode drainage capacity, raise landslide risk and cut off communities in rural and mauka areas with little notice.
Know something we missed? Have a correction or additional information?
Submit a Tip
