High surf advisory in effect until 6 p.m. Thursday for north shores of Big Island

The National Weather Service has issued a high surf advisory until 6 p.m. Thursday for north-facing shores on Hawaiʻi Island that can expect large breaking waves of 12 to 18 feet.

Forecasters also say minor coastal flooding during peak monthly high tides in the early morning hours this week is possible for low-lying coastal areas on all Hawaiian islands.

A large north-northwest medium period swell will build into the Hawaiian Islands through Thursday increasing surf heights above advisory thresholds along exposed north and west facing shores of Kauaʻi, Niʻihau, Oʻahu and Molokaʻi, including north facing shores of Maui and the Big Island.

Large breaking waves of 8 to 12 feet are expected on west-facing shores.

Surf heights will likely fall below advisory thresholds by Thursday night as the swell energy decreases.

Strong breaking waves and strong currents will make swimming dangerous.

Avoid driving through flooded roadways. If you are forced to drive through salt water, be sure to rinse your vehicle with fresh water. Move electronics, vehicles or other valuables to
higher ground.

Monitor vessels to ensure mooring lines don’t get too tight and watch out for overwash around boat ramps. Secure canoes or other watercraft stowed on beaches.

Heed all advice from ocean safety officials. When in doubt, don’t go out.

The University of Hawaiʻi Sea Grant College Program is asking the public to send coastal flooding photos to PacificIslandsKingTides.org for its Hawaiʻi and Pacific Islands King
Tides Project.