Less than two weeks after back-to-back Kona lows unleashed the worst flooding Hawaii had seen in 20 years, a new storm system threatens to bring several inches of rain and dangerous flash flooding beginning Tuesday, the National Weather Service warned.
A low pressure system developing northwest of Hawaii is expected to draw a deep plume of tropical moisture northward, with the most dangerous period of heavy rain to arrive Wednesday night and last through Thursday night.
Several rounds of heavy rain and thunderstorms will impact the islands later this week. (Baron/Lynx )
The timing is grim. Despite several days of drier trade wind weather since the March storms, soils remain quite vulnerable across much of the state, meaning any period of heavy rainfall could quickly lead to enhanced runoff and renewed flooding.
The March disaster caused an estimated $1 billion in damage, according to Hawaii Gov. Josh Green. More than 230 people were rescued from floodwaters, 5,500 residents near the Wahiawa Dam were evacuated under emergency orders, and communities on Oahu’s North Shore saw homes pushed off their foundations.
The University of Hawaii estimated the storms delivered more than 2 trillion gallons of rain over 14 days, reaching as high as 3,000% of normal rainfall levels in some areas. Parts of Maui recorded more than 46 inches during the first storm alone.
Gianne Lei Duquez, left, holds a flashlight as cousin Myla Grace Zara removes debris from her mud-riddled room in Haleiwa, Hawaii Saturday, March 21, 2026. Zara and her family were trapped on their roof during the fast-moving flood and were rescued by fellow community volunteers. (Stephen Lam/S.F. Chronicle)
This week’s storm system will work differently than March’s Kona lows, but it shares the same critical ingredient. Deep tropical moisture will be pulled northward into rugged terrain equipped to squeeze out heavy rain.
Forecasters warn the rain could be widespread and heavy, with thunderstorms possible on the north and windward sides of the islands.
While the worst of the storm is expected to conclude Thursday, the bigger concern may be what comes after. Unlike a typical storm that moves through and clears out, this system could keep a tap of deep tropical moisture open well into mid-April, raising the possibility of additional rounds of heavy rain next weekend or beyond.
This article originally published at Flood-weary Hawaii faces another drenching this week.
