Flash Flood Warning Hawaii | Effective 03/20/2026 09:11

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 8 AM HST THIS MORNING FOR THE ISLAND OF OAHU IN HONOLULU COUNTY... At 611 AM HST, emergency management reported life-threatening flash flooding across northern Oahu, particularly in the Haleiwa and Waialua areas. Floodwaters have cut off road access in and out of Haleiwa, and widespread flooding of roadways and low-lying areas is ongoing. Although rainfall rates have temporarily decreased, significant runoff continues to produce high water levels and dangerous flooding impacts. Additional bands of heavy rainfall moving in from the southwest will continue over the area, which could lead to renewed rises in water levels and worsening flooding conditions. The Wahiawa Reservoir (Lake Wilson) and Helemano 6 Reservoir remain elevated, with water levels still high despite beginning to level off. Additional rises in these reservoirs could further exacerbate downstream flooding along the streams, particularly near Otake Camp in Waialua. For the windward side of Oahu, heavy showers continue to develop and move through, with rainfall rates of 1 to 2 inches per hour. Water levels in the streams remain high, especially in the Waiahole, Waikane, and Kahana streams. Runoff impacting vulnerable low lying areas and roads will continue through the morning hours. This is a FLASH FLOOD EMERGENCY for Northern Oahu. This is a PARTICULARLY DANGEROUS SITUATION. SEEK HIGHER GROUND NOW! HAZARD...Heavy rain producing life threatening flash flooding. SOURCE...Emergency management. IMPACT...Severe flooding in drainages, streams, rivers, roads, properties, and other low lying areas. Numerous public road closures expected, as well as landslides in steep terrain. Significant property damage expected to homes and other properties in low lying areas. Some locations that will experience flash flooding include... northern half of Oahu, along and north of a line from Waianae Valley to Mililani Mauka to Waiahole.