Hawaii Flooding: North Shore Evacuations and Dam Concerns Amidst Record Rainfall

Hawaii is grappling with its worst flooding in over two decades, prompting urgent evacuation orders and raising concerns about a vulnerable 120-year-old dam. Heavy rainfall, falling on already saturated soil, has inundated Oahu’s North Shore and parts of Maui, impacting thousands of residents and infrastructure.

Oahu’s North Shore Under Water

Authorities urged residents in hard-hit areas of Oahu to “Abandon NOW” as muddy floodwaters submerged vast stretches of the North Shore, an area famed for its big-wave surfing. Evacuation orders were issued for 5,500 people north of Honolulu. The area received 8 to 12 inches (20 to 30cm) of rain, according to the National Weather Service [National Weather Service].

The remaining access road out of Waialua was identified as being at high risk of failure if rainfall continued, according to emergency alerts. While waters receded in some areas Saturday morning, meteorologist Tina Stall of the National Weather Service in Honolulu cautioned against complacency, stating, “There’s still potential for more flooding impacts.” [National Weather Service]

Racquel Achiu, a Waialua farmer, described finding her goats in knee-high water and her family’s dogs in danger of drowning, requiring a rescue by her nephew and son-in-law in chest-high water.

Maui Evacuations and Lingering Wildfire Concerns

On Maui, evacuation advisories were upgraded to warnings for portions of Lahaina, a community still recovering from the devastating 2023 wildfires. This action was taken due to retention basins nearing capacity.

Dam Vulnerability and Rescue Efforts

Officials have been closely monitoring the Wahiawa dam, located 17 miles (28km) north-west of Honolulu, which has been identified as vulnerable for decades. While water levels receded late Friday before rising again overnight, the “breadth of hazardous conditions” across Oahu became the primary concern. [Move Hawaii]

More than 200 people were rescued from the rising waters, though no deaths or missing persons have been reported. Search and rescue teams conducted operations by air and water.

Economic Impact and Federal Support

Governor Josh Green estimates the storm’s cost could exceed $1 billion, encompassing damage to airports, schools, roads, homes, and a hospital in Kula, Maui. He stated this would have a “very serious consequence” for the state. The White House has reportedly assured the state of federal support. [Go Hawaii]

Governor Green described the flooding as the state’s most severe since 2004, when homes and a University of Hawaii library were flooded.

Kona Lows and Climate Change

The flooding was attributed to “Kona lows,” winter storm systems bringing moisture-laden air. Experts note that the intensity and frequency of heavy rainfall in Hawaii have increased due to human-caused global heating. [North Shore Oahu – Wikipedia]

North Shore Oahu: A Brief Overview

The North Shore of Oahu, situated between Kaʻena Point and Kahuku, is best known for its massive waves and attracts big-wave surfers worldwide. Haleʻiwa is the largest town in the area. [North Shore Oahu – Wikipedia]