Why It Matters
Hawaii faces another dangerous weather system that could dump multiple months of rainfall in just days, threatening communities still recovering from catastrophic March flooding. The state is activating emergency operations as forecasters warn every island could see significant flooding and landslides.
What Happened
A slow-moving Kona storm system began battering the Hawaiian Islands Tuesday with heavy rain that officials say will intensify through Friday. The National Weather Service issued a flood watch for all islands through Friday afternoon.
Forecasters expect widespread rainfall totals of 4 to 8 inches statewide, with some areas potentially receiving more than 10 inches. The Big Island and Kauai face the highest risk for extreme rainfall accumulations.
Flash flood warnings were already issued Tuesday night for parts of Maui and the Big Island after floodwater entered at least one home in the Puna District. Multiple weather stations recorded more than six inches of rain in the storm’s opening hours.
Honolulu Mayor Rick Blangiardi warned residents to prepare for possible evacuations during a Monday press conference. The city activated its Emergency Operations Center Wednesday and deployed first responders to vulnerable areas ahead of the storm’s most intense phase.
By the Numbers
- 4 to 8 inches: Expected widespread rainfall totals by Friday evening
- 10+ inches: Possible accumulations in hardest-hit areas
- 3: Number of Kona storms to strike Hawaii since mid-March
- 25 inches: Rain recorded at one Oahu location during March’s second storm, most falling within 24 hours
- 200+: Rescues conducted during March floods that damaged or destroyed hundreds of properties
Zoom Out
This marks the third Kona storm to hit Hawaii since mid-March. The second storm triggered the state’s worst flooding in two decades when approximately one foot of rain fell across Oahu from March 19 to 24, prompting more than 200 rescues and causing widespread property damage. Parts of Maui experienced serious flooding and wind damage from the first storm earlier in March.
Kona storms are weather systems that form northwest of the islands and move slowly, allowing them to draw moisture from the equatorial Pacific and deliver prolonged rainfall. Their slow movement makes them particularly dangerous for flash flooding.
Areas hardest hit in March remain especially vulnerable because saturated ground will flood faster and channel runoff into streams more quickly. Mayor Blangiardi noted that because of existing conditions, every inch of new rainfall will have a compounded effect.
What’s Next
Rounds of showers and thunderstorms will continue through Thursday morning, with intensity increasing Thursday afternoon as the Kona storm strengthens. The storm system could produce extreme rainfall rates as bands of heavy rain track repeatedly over the same areas.
Rain should remain in the forecast for most islands through the weekend but will become less intense by Saturday as the storm moves north and away from Hawaii.
Emergency officials are monitoring vulnerable areas and standing by to conduct evacuations if flooding reaches dangerous levels.
About the Author
