Hawaii Braces for Extreme Rainfall and Flooding from Kona Low

Torrential rain, flash flooding, and severe thunderstorms expected across the islands this week

Published on Mar. 9, 2026

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A powerful Kona low weather system is forecast to bring torrential rainfall, flash flooding, strong winds, and severe thunderstorms to Hawaii this week. The National Weather Service has issued flood watches for Kauai and Oahu, with the potential for over 30 inches of rain on the state's volcanoes. Significant snowfall is also expected on the Big Island's summits.

Why it matters

Hawaii is no stranger to heavy rain, but the intensity and duration of this Kona low system could lead to life-threatening flooding and disruptions across the islands. The extreme weather pattern is being fueled by an abundance of tropical moisture drawn northward, raising concerns about potential impacts on infrastructure, agriculture, and public safety.

The details

The Kona low will bring two rounds of stormy weather to Hawaii from Tuesday through Saturday. Rainfall rates could reach 2-3 inches per hour within the heaviest bands, leading to flash flooding. Severe thunderstorms may also generate hail, damaging winds, and even isolated tornadoes, especially on Kauai and Oahu. Significant snow accumulations are forecast for the summits of the Big Island.

  • The first round of heavy rain will begin over Kauai on Tuesday morning before reaching Oahu on Tuesday night.
  • A lull in storminess is expected on Thursday, but an even stronger disturbance is forecast for Friday into Saturday.
  • The flood watches for Kauai and Oahu are in effect through Saturday afternoon.

The players

National Weather Service

The federal agency that issued the flood watches and warnings for the extreme weather pattern affecting Hawaii.

Laura Farris

A meteorologist at the National Weather Service office in Hawaii who provided estimates for potential rainfall totals.

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What they’re saying

“The high-end potential of this Kona storm is significantly outside the realm of 'normal' wet season weather.”

— National Weather Service (sfchronicle.com)

“Through Saturday, 'we could easily see over 20 inches in the harder-hit areas, but that's just a ballpark estimate.”

— Laura Farris, Meteorologist, National Weather Service (sfchronicle.com)

What’s next

The National Weather Service will continue to monitor the Kona low system and issue additional flood watches, warnings, and updates as the extreme weather pattern unfolds across Hawaii.

The takeaway

This Kona low event highlights the increasing frequency and intensity of extreme weather patterns that can threaten Hawaii's infrastructure, agriculture, and public safety. Residents and visitors should heed all weather warnings and be prepared for potential disruptions and flooding in the coming days.