Big Surf Coming; Hawaii Island Could See 20-Foot Waves

The National Weather Service has issued a high-surf warning for parts of the state in anticipation of some of the biggest waves in years.

Forecasters said the waves could reach heights of 40 to 50 feet at west- and north-facing shores of Niihau and Kauai, and at north-facing shores of Oahu, Molokai and Maui.

The western side of the Big Island is included in the warning, although waves there are expected to be in the 12- to 18-foot range.

The swell has also prompted the issuing of a high-surf advisory for the north-facing shores of the Big Island where surf of 15-20 feet could occur.

The monster surf is expected to build rapidly as it moves its way from the east down the island chain.

That means its effects will begin to be felt before midnight tonight on Niihau and Kauai, by sunrise tomorrow on Oahu and by mid-morning on Molokai and Maui.

The surges are expected to begin impacting the shores of the Big Island by Wednesday afternoon.

The weather service said the high surf may persist at warning levels until Friday.

The green area designates high-surf warnings and the purple high-surf advisories. NWS graphic.

Forecasters are warning ocean-goers and those living near the shore to expect a “very large shorebreak” resulting in significant coastal inundation.

“Road closures are likely and breaking waves may make it impossible to enter or leave harbors,” the weather service said.

The last high-surf event on Dec. 20 prompted the county and state to close all but one of the beach parks in West Hawaii where mostly 8- to 10-foot waves were occurring.

However, it also sent 15-foot waves up to the vegetation line at Hapuna Beach and to the parking lot at nearby Waialea Bay. At least one wave also reached Alii Drive in Kailua-Kona.

The surf also severely damaged the Puako boat ramp in South Kohala.

Forecasters said this upcoming swell has the potential for even greater heights than the December event.