Ongoing Kona Low Brings Significant Flooding to Hawaii
A persistent Kona low coupled with strong water vapor transport from an atmospheric river has brought devastating floods to the state of Hawaii in late March 2026. Rain totals over the past ten days have exceeded 40 inches in some locations, prompting evacuation orders for thousands. Over two hundred people have been rescued from the rising flood waters.
The CIMSS MIMIC-TPW2 product gives a good overview of the situation. Here’s it possible to see how the cyclone circulation northeast of Hawaii is drawing the moisture-laden water northward from the near-equatorial region. As that air reaches the Hawaiian archipelago, the orography of the islands contributes to vertical lifting and enhances the rainfall.
Synthetic Aperture Winds from the Sentinel-1 satellite on 21 March show the largely southerly flow running into the island of Maui, where the influence of the terrain on rainfall is going to be significant; similar effects are happening on the other islands.
The Japan Aerospace Exploration Agency (JAXA) Global Change Observing Mission (GCOM) satellite is one that is monitored by CIMSS’s and NOAA’s network of ground-based direct broadcast antennas. With an antenna in Honolulu, CIMSS is able to produce low-latency products from polar orbiting satellites, including from GCOM’s Advanced Microwave Scanning Radiometer (AMSR2). Here’s an animation of the 36.5 GHz microwave brightness temperature, which is sensitive to deep precipitation-producing clouds, from 15 to 21 March 2026. This and other direct broadcast products from Hawaii produced by CIMSS can be seen here. It’s clear that for every day for nearly a week, persistent strong rain has been present over Hawaii.
As of the morning of Sunday 22 March, the National Weather Service anticipates the low continuing to move off to the northeast with atmospheric flow over Hawaii returning to a more typical trade wind pattern. Due to the devastation wrought by this event, the islands and their people will take much longer to return to normal.