All eyes are on Hawaii as Hurricane Madeline approaches the Big Island. High surf and coastal flooding are concerns with any hurricanes that approach Hawaii, as storm surge can suddenly build along island chains, with water levels that are quite localized.
Hurricane Madeline approached Hawaii's Big Island as a category-3 hurricane on the afternoon of Tuesday, August 30, 2016, in this color-enhanced satellite image from NOAA.
Due to the deep bathymetry, or offshore water depth, storm surge levels tend to stay suppressed in Hawaii, while waves build to enormous heights. In historic literature, including scientific documentation, coastal flood observations are often referred to as “surf.”
The Central Pacific Hurricane Center forecasts Hurricane Madeline to approach the Big Island, either making landfall near the southern tip, or passing just south of the island.
In 1992, Hurricane Iniki generated the highest recorded storm surge levels in Hawaii, with water levels rising to 6 ft above normal astronomical tides on the South Kauai Coast. During that event, surf levels were recorded at 30 ft (U.S. Department of Commerce 1993).
On the Big Island, where Madeline’s impact will be felt the strongest, Hurricane Diana in 1972 generated surf levels also reached 30 ft along the Puna coast, while storm surge levels at Hilo ranged from 4 to 5 ft (Central Pacific Hurricane Center 1972). Although this may not sound impressive, modest storm surges combined with tremendous wave heights can still be destructive, because waves are riding on top of the storm surge, enabling them to push a destructive force of water inland, well beyond the storm surge water limit. Diana’s combined storm surge and high surf swept four homes from their foundations and eroded 200 feet of a private road (Central Pacific Hurricane Center 1972).
More recently, Hurricane Iselle (2014) generated a 4-ft storm surge at Kapoho and Vacationland, near the eastern tip of the Big Island. Massive waves enabled water to push inland, causing flooding and erosion.