(BIVN) – A High Surf Advisory is in effect for north and west facing shores of Hawaiʻi Island, as a High Surf Warning is in effect for the rest of the Hawaiian islands.

The National Weather Service says the “long-duration high surf event with a very large northwest swell continues with only gradual lowering today. Although shadowed by the smaller islands, the big island will still see advisory level surf along exposed north and west facing shores.”

Surf heights of 15 to 20 feet are expected along exposed north facing shores, and 6 to 10 feet along exposed west facing shores.

“Expect strong breaking waves, shore break, and strong longshore and rip currents making swimming difficult and dangerous,” forecasters say.

Oʻahu, Maui, Kauaʻi, Niʻihau, and Molokaʻi could see surf as high as 30 feet today.