HONOLULU (HawaiiNewsNow) - An extremely large, long-period swell will bring dangerously large surf to north and west shores this weekend.
The National Weather Service in Honolulu has issued a High Surf Warning for the north and west shores of Niihau, Kauai, Oahu and Molokai, and the north shores of Maui and the Big Island.
The warning is in effect until 6 p.m. Sunday.
Surf is forecast to build quickly late Friday night into Saturday and peak Saturday evening. Forecasters say waves of 40 to 50 feet are possible for north and west shores of Niihau and Kauai and the north shores of Oahu, Molokai and Maui. Surf on the west shores of those islands will rise to 25 to 35 feet.
Waves this large could have coastal overwash and cause significant impacts to shorelines, especially those already impacted by erosion. The largest impact will come during the early morning high tides on Saturday and Sunday.
Those will occur statewide between 1:30 a.m. and 3 a.m. on both days, with high tides reaching anywhere between 1.6 and 2.6 feet, depending on the location.
Surf for the north shore of the Big Island is forecast to rise to 10 to 16 feet.
With waves this high, ocean water can surge and sweep across beaches, coastal benches and lava flows, which can impact roadways and coastal properties.
Powerful longshore and rip currents, large breaking waves and significant shorebreaks will make it hazardous and deadly to enter the water. Large breaking waves and currents at harbor entrances will also make boat handling difficult and challenging.
On Kauai, Ocean Safety crews rescued a Minnesota man 700 yards off shore of Anini Beach at about 12:30 p.m. Friday. He was brought to shore and assisted by medics.
Lifeguards returned to the water on jet skis and rescued two more swimmers who had been caught in a rip current and were being swept out into large surf.
The Kauai Fire Department said the swimmers were attempting to rescue the first swimmer using a boogie board and rescue tube. The pair refused further treatment after being returned to shore.
On Oahu, Ocean Safety lifeguards performed 12 rescues (including this rescue) and 1,575 preventative actions, such as warnings to beachgoers, on the North Shore Friday. On West Oahu, there were four rescues and 820 preventative actions.
Also, several city and county agencies, including the Department of Emergency Management, are monitoring Sunset Beach, which has suffered unprecedented amounts of erosion from large swells earlier this season. A press release also said the Honolulu fire and police departments were also also preparing for possible emergency responses.