Flood Advisory Issued for Kaʻū, Puna as Powerful Kona Storm Approaches

The National Weather Service issued a flood advisory and hydrologic warnings for portions of Kaʻū and Puna on Wednesday as a Kona low moved over the state, the leading edge of a powerful storm system forecast to batter the Hawaiian island chain through the weekend.

The warnings arrive as Hawaiʻi island already carries a broader Flood Watch, with forecasters describing the system as capable of producing prolonged heavy rainfall, flash flooding, severe thunderstorms, and damaging winds. "Considerable flash flooding is possible this week beginning early Tuesday as a powerful Kona low develops northwest of the state and draws deep tropical moisture across the islands," the National Weather Service said in a statement.

The storm followed a westward-to-east progression through the chain. Flood watches were first issued for Niihau and Kauai beginning Tuesday morning, then for Oahu starting Tuesday evening, with warnings of excessive rainfall potentially triggering flash flooding, road closures, and landslides in steep terrain. By Wednesday night, forecasters said, heavy showers and thunderstorms were expected to push into the south and southeast slopes of the Big Island, putting communities in Puna and Kaʻū directly in the path of the heaviest rainfall.

The National Weather Service said the storm is expected to produce prolonged heavy rainfall with the highest likelihood of flooding impacts across the smaller islands and urban areas. Beginning midweek, strong to severe thunderstorms and gusty southerly winds became possible, with the potential for more damaging conditions later in the week. Additional surges of moisture could prolong the rainfall and flooding threat into the weekend.

A state proclamation has been issued to allow coordination of resources across agencies and support county emergency response efforts as conditions develop. Residents across Kaʻū and Puna are urged to monitor National Weather Service forecasts and clear storm drains and drainage areas now to reduce localized flooding when the heaviest rainfall arrives.

Marine conditions around the island are also deteriorating. A small craft advisory is in effect until 6 p.m. Wednesday for the Pailolo Channel, the Alenuihaha Channel, and the surrounding waters of Hawaiʻi island, where east winds up to 25 knots are creating hazardous conditions for smaller vessels.

The full text of the flood advisory and hydrologic warnings for Kaʻū and Puna, including specific rainfall amounts and impacted drainages, was not immediately available in complete form. Hawaii County Civil Defense is the primary contact for any evacuation orders, road closures, or emergency shelter activations as the storm continues to develop.