HONOLULU (HawaiiNewsNow) - A High Surf Advisory is in effect for what's expected to be the largest south swell so far this year.
The National Weather Service said the advisory will be in effect for south-facing shores of all islands until 4 p.m.Wednesday.
A powerful low pressure area in the South Pacific generated the swell, which brought 8- to 12-foot waves for south shores with some higher sets.
The swell is expected to slowly diminish through Wednesday, with 5- to 8-foot waves.
Surf began rising Sunday. But mid-day some surfers reported that spots like Kewalos and Point Panic were closing out as the waves continued to build.
The long period swell is also expected to bring the potential for moderate to heavy surges in south-facing harbors, such as the Ala Wai Harbor and Kewalo Basin on Oahu. Waves may also break in and near channel entrances, and surfers and body boarders may also use the channels to reach surf breaks.
Officials say swimmers should expect strong breaking waves, shore break and strong longshore and rip currents, making swimming difficult and dangerous.
Ocean Safety officials have issued mostly a "High Hazard" (Red Alert) for near and offshore south-facing beaches on Oahu according to its website, HawaiiBeachSafety.com. That alert is for beaches at Ala Moana, Magic Island Lagoon, Waikiki's Dukes, Kuhio, Queens and Kapiolani Park areas as well as Sans Souci and Sandy Beach. A "Caution" (Yellow Alert) is issued for near and offshore waters of Hanauma Bay and offshore waters of Sandy Beach.
For more alert designations for all beaches across Hawaii, go to HawaiiBeachSafety.com.
According to the website, a "High Alert" means "Swimmers are advised to stay out of the ocean. Currents and surge on the beach are quite strong and shore break (waves breaking on the beach) can cause injury. Avoid exposed beaches and rocky shoreline. Remain beyond the reach of the waves as indicated by wet sand or rocks. Be aware of the variable nature of wave groups and lulls."
Beachgoers are advised to "know your limits and seek ocean recreation areas best suited for your abilities."
National Weather Service officials caution beachgoers, swimmers and surfers should heed all advice given by Ocean Safety officials and exercise caution.
"Boaters should expect surfers and body boarders utilizing harbor channels to access surfing areas," NWS officials said.