An intense storm northwest of the Hawaiian Islands triggered the super swell, which had been rapidly building throughout the day and into the evening.
The National Weather Service said around 9 a.m. Buoy 101, which measures open ocean swells northwest of the Hawaiian Islands, reported an ocean swell of 31 feet at 17 seconds. That translates to 50+ feet on the north shore around 7 p.m.
North shore beaches on Thursday saw 30 to 40 foot faces, west shores 15 to 25 feet and west shores of the Big Island 10 to 15 feet. Currently a high surf warning is in effect until 6 a.m. Saturday for the north and west shores of Niihau, Kauai, Oahu and Molokai, the north shore of Maui. A high surf advisory has been issued for the Big Island until 6 a.m. Saturday.
As of noon Wednesday, all coastal roads were open and passable. But Waimea Bay was closed on Wednesday as Ocean Safety lifeguards reported that surf washed up onto the beach and into the parking lot and has undermined several large trees.