Evacuation warning issued after possible Wahiawā Dam failure alert on Oʻahu, Hawaiʻi
A potential failure of Wahiawā Dam on Oʻahu, Hawaiʻi, triggered an evacuation warning at 18:55 LT on March 13, 2026, for downstream communities, including Haleʻiwa and Waialua. Authorities said conditions existed that could lead to dam failure capable of causing catastrophic flooding, prompting residents to prepare for possible evacuation.
Image credit: Honolulu Department of Emergency Management
A potential failure of Wahiawā Dam on Oʻahu, Hawaiʻi, prompted emergency officials to issue an evacuation warning for downstream communities during the evening of March 13.
The alert, issued by the Oʻahu Department of Emergency Management at 18:55 LT (04:55 UTC on March 14), warned that conditions existed that could lead to failure of the dam and catastrophic flooding in areas located along the downstream floodplain.
The warning applied to areas downstream of Wahiawā Dam, including parts of the North Shore communities of Haleʻiwa and Waialua. Officials identified the evacuation zone in Haleʻiwa as the area between Puuiki Street and Kamehameha Highway, while affected areas in Waialua extend between Kukea Circle and Otake Camp.
No mandatory evacuation order was issued at the time of the alert, but residents were instructed to prepare to leave on short notice.
Emergency management authorities advised residents in the evacuation zone to prepare emergency supplies and ensure evacuation readiness. Recommended actions included assembling a go-bag with medications, hygiene items, and important documents, preparing pets for transport, and assisting neighbors who may require help evacuating.
Residents who might need additional time to evacuate were advised to leave early if they felt unsafe.
Authorities warned that failure of Wahiawā Dam could produce rapid downstream flooding affecting populated areas along the Anahulu River system, which drains Wahiawā Reservoir toward the North Shore. Because dam-failure floods can occur with little warning, emergency managers emphasized the need for advance preparation even though an evacuation order had not been issued.
Emergency shelters were opened as a precaution for residents needing a safe place to stay during the event. Shelters identified in the alert included Waialua High and Intermediate School, Wahiawā District Park, and Kahuku Elementary School. Officials advised residents outside the affected areas to stay out of the evacuation zone while monitoring updates from emergency authorities.
Later updates issued by the Oʻahu Department of Emergency Management at 22:02 LT (08:02 UTC on March 14) reported that water levels at Wahiawā Dam were trending downward while officials continued monitoring the structure. Although heavy rain remained forecast for several hours, authorities said the improving reservoir conditions made it less likely that an evacuation would become necessary.
Officials advised residents in downstream communities to remain prepared in case conditions changed while continuing to monitor official alerts and local broadcast updates.
Emergency managers said additional updates would be issued after the passing of the current band of showers or sooner if conditions at the dam deteriorated.
The elevated reservoir levels occurred as a slow-moving Kona low pressure system impacted the Hawaiian Islands, producing widespread heavy rainfall and severe weather across the state.
The storm prompted statewide disruptions on March 13, including school closures and hazardous travel conditions, as bands of intense rainfall moved across Oʻahu and other islands.
Wahiawā Dam forms the Wahiawā Reservoir, also known as Lake Wilson, a major inland water body in central Oʻahu constructed in the early twentieth century for plantation irrigation.
The reservoir drains through streams that feed the Anahulu River, which flows through Haleʻiwa before reaching the Pacific Ocean along the island’s North Shore.
References:
1 HNL Alert from the Oahu Department of Emergency Management – HNL Alert – Issued at 04:52 UTC on March 14, 2026
2 Update: HNL Alert from the Oahu Department of Emergency Management – HNL Alert – Issued at 08:02 UTC on March 14, 2026
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